Screw rotor assembly
First Claim
Patent Images
1. A screw rotor assembly, comprising:
- a male rotor (1) having hellical lands and a female rotor (2) having helical grooves which mesh with each other and rotate about two parallel axes, a major portion of each tooth profile of said female rotor being formed inside a pitch circle of said female rotor, and a major portion of each tooth profile of said male rotor being formed outside a pitch circle of said male rotor, wherein in a plane perpendicular to rotating axes of said rotors;
a tooth profile of said female rotor (2) is formed such that a first curve (H2 -A2) connecting an outermost point (H2) at a tip of an addendum (Af) and a first point (A2) located on the pitch circle is a generated curve of a second point (A1) located on the pitch circle of the male rotor tooth profile;
a portion between said first point (A2) and a third point (B2) is formed by a first circular arc having a first radius (R7) and a center (O7) of said first arc which is located on a line tangent to the pitch circle of the female rotor at said first point (A2) and located outside the concave of the groove;
a portion between said second point (B2) and a fourth point (C'"'"'2) is formed by a first envelope (B2 -C2) developed by a second circular arc (B1 -C1) which is a part of the male rotor tooth profile;
a portion between fifth and sixth points (D'"'"'2) and (E2) is formed by a third circular arc (D'"'"'2 -E2) having a second radius (R1) and a center (O1) of said third arc is located on a line (3-4) connecting centers of rotation of said male and female rotors and outside the pitch circle of said female rotor;
a portion between said fourth and fifth points (C'"'"'2) and (D'"'"'2) is formed by a common tangent of the first envelope (B2 -C'"'"'2) and said third circular arc (D'"'"'2 -E2) and connected with said third arc (D'"'"'2 -E2) at the fifth point (D'"'"'2);
a portion between the sixth point (E2) and a seventh point (F2) is formed by a fourth circular arc (E2 -F2) connected with the third arc (D'"'"'2 -E2) at the sixth point (E2) and having a radius (R2) and a center (O2) of a fifth arc located on an extension of a line (O1 -E2) intersecting at an angle (O1 ) with said line (3-4) passing through the centers of the rotors and connecting the centers of rotation of said male and female rotors at a position opposite to the center (O1) of the third arc (D'"'"'2 -E2) with respect to the sixth point (E2); and
a portion between the sixth point (F2) and a seventh (G2) is formed by a sixth circular arc (F2 -G2) connected with a seventh circular arc (G2 -H2) having a radius equal to the outer diameter of said female rotor at an eighth point (G2) and having a radius (R8) and a center (O8) of the arc being located on a line connecting the center (O2) of the fourth arc and the seventh point (F2) and located outside of the groove of the female rotor tooth profile; and
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Accused Products
Abstract
A screw rotor assembly 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 curve (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 curves (B2 -C'"'"'2) and (D'"'"'2 -E2); a curve (E2 -F2) is formed by a circular arc having a point O2 as the center of the arc and a radius R2 ; and a curve (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 curve (H1 -A1) is formed by a generated curve of a point H2 of the female rotor; a curve (A1 -B1) is formed by an envelope developed by the arc (A2 -B2) of the female rotor; a curve (B1 -C1) is formed by a circular arc having a point O4 as the center of the arc and a radius R4 ; a curve (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 curves (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 rotor assembly prevents abnormal noise and vibration of the compressor or expander and can be easily manufactured.
15 Citations
2 Claims
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1. A screw rotor assembly, comprising:
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a male rotor (1) having hellical lands and a female rotor (2) having helical grooves which mesh with each other and rotate about two parallel axes, a major portion of each tooth profile of said female rotor being formed inside a pitch circle of said female rotor, and a major portion of each tooth profile of said male rotor being formed outside a pitch circle of said male rotor, wherein in a plane perpendicular to rotating axes of said rotors; a tooth profile of said female rotor (2) is formed such that a first curve (H2 -A2) connecting an outermost point (H2) at a tip of an addendum (Af) and a first point (A2) located on the pitch circle is a generated curve of a second point (A1) located on the pitch circle of the male rotor tooth profile;
a portion between said first point (A2) and a third point (B2) is formed by a first circular arc having a first radius (R7) and a center (O7) of said first arc which is located on a line tangent to the pitch circle of the female rotor at said first point (A2) and located outside the concave of the groove;
a portion between said second point (B2) and a fourth point (C'"'"'2) is formed by a first envelope (B2 -C2) developed by a second circular arc (B1 -C1) which is a part of the male rotor tooth profile;
a portion between fifth and sixth points (D'"'"'2) and (E2) is formed by a third circular arc (D'"'"'2 -E2) having a second radius (R1) and a center (O1) of said third arc is located on a line (3-4) connecting centers of rotation of said male and female rotors and outside the pitch circle of said female rotor;
a portion between said fourth and fifth points (C'"'"'2) and (D'"'"'2) is formed by a common tangent of the first envelope (B2 -C'"'"'2) and said third circular arc (D'"'"'2 -E2) and connected with said third arc (D'"'"'2 -E2) at the fifth point (D'"'"'2);
a portion between the sixth point (E2) and a seventh point (F2) is formed by a fourth circular arc (E2 -F2) connected with the third arc (D'"'"'2 -E2) at the sixth point (E2) and having a radius (R2) and a center (O2) of a fifth arc located on an extension of a line (O1 -E2) intersecting at an angle (O1 ) with said line (3-4) passing through the centers of the rotors and connecting the centers of rotation of said male and female rotors at a position opposite to the center (O1) of the third arc (D'"'"'2 -E2) with respect to the sixth point (E2); and
a portion between the sixth point (F2) and a seventh (G2) is formed by a sixth circular arc (F2 -G2) connected with a seventh circular arc (G2 -H2) having a radius equal to the outer diameter of said female rotor at an eighth point (G2) and having a radius (R8) and a center (O8) of the arc being located on a line connecting the center (O2) of the fourth arc and the seventh point (F2) and located outside of the groove of the female rotor tooth profile; and
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2. a tooth profile of the male rotor (1) is formed such that a second curve (H1 -A1) connecting a ninth point (H1) located on a bottom land of a dedendum (Dm) and said second point (A1) located on said pitch circle is a generated curve of a tenth point (H2) located on the female rotor tooth profile, a portion between said second points (A1) and third (B1) is a second envelope developed by an eighth arc (A2 -B2) which is a part of the female rotor tooth profile;
- a portion between an eleventh point (B1) and a twelfth (C1) is formed by a circular arc (B1 -C1) connected with said second envelope (A1 -B1) at said eleventh point (B1) and having a radius (R4) and a center O4 of the second arc located on a line intersecting at an angle (θ
r5) with said line (3-4) connecting the rotating centers (3,
4) of said male and female rotors (1,
2) and located at a predetermined distance from said line (3-4) connecting the rotating centers of said male and female rotors (1,
2);
a portion between said twelfth point (C1) and a thirteenth point (D1) is formed by a circular arc (C1 -D1) having a radius (R5) and a center of the arc (3) at the rotating center of said male rotor;
a portion between the thirteenth point (D1) and a fourteenth point (E1) is formed by a third evelope (D1 -E1) developed by a ninth arc (D2 -E2) which is a part of the female rotor tooth profile;
a portion between the fourteenth point (E1 ) and a fifteenth point (F1) is formed by a fourth envelope (E1 -F1) developed by a tenth arc (E2 -F2) which is a part of the female rotor tooth profile;
a portion between the points (F1) and G1) is formed by a fifth envelope (F1 -G1) developed by the arc (F2 -G2); and
tooth profiles of said male and female rotors (1,
2) are formed by smoothly and tangentially connecting said arcs and curves.
- a portion between an eleventh point (B1) and a twelfth (C1) is formed by a circular arc (B1 -C1) connected with said second envelope (A1 -B1) at said eleventh point (B1) and having a radius (R4) and a center O4 of the second arc located on a line intersecting at an angle (θ
Specification
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Current AssigneeHokuetsu Industries Co., Ltd.
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Original AssigneeHokuetsu Industries Co., Ltd.
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InventorsTanaka, Masanori, Kanai, Junichi, Maehara, Atsushi
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Primary Examiner(s)Smith, Leonard E.
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Assistant Examiner(s)NOT, DEFINED
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Application NumberUS06/714,540Time in Patent Office362 DaysField of Search418/150, 418/201US Class Current418/150CPC Class CodesF04C 18/084 Toothed wheelsF04C 18/16 with helical teeth, e.g. ch...
