Intermeshing screw rotor machine with specific thread profile
First Claim
1. In a screw rotor machine including a housing defining a pair of intersecting parallel bores, and a pair of rotors mounted for rotation within said bores of said housing, said rotors having intermeshing helical threads and grooves, with the threads and grooves of one of said rotors lying substantially outside the pitch circle of said one rotor and with the threads and grooves of the other of said rotors lying substantially inside the pitch circle of said other rotor, said threads of said other rotor including a crest portion located substantially outside the pitch circle of said other rotor, with flanks of the threads of said other rotor defining, respectively, one side each of adjacent grooves located on opposite sides of said thread, one of said flanks of said threads of said other rotor operating to define the side of an adjacent groove which is the trailing side of said groove when said machine is operated as a compressor and the leading side when said machine is operated as a motor, said trailing side of said groove being substantially generated from a point in said groove closest to the axis of said other rotor to a point where said groove intersects the pitch circle of said other rotor by a crest portion of the respective thread of said one rotor which is radially most remote from the axis of said one rotor, the improvement which comprises that said radially remote crest portion of said one rotor is rounded with a relatively small radius dimension to generate the flanks of the threads of said other rotor to be tangent to a plurality of circles having centers which lie on a radial line which is curved in the direction of rotation of said other rotor, said circles having diameters which decrease taken from the radially innermost to the radially outermost of said circles, with said crest portion of said threads of said other rotor being shaped in conformity with the radially outermost of said plurality of circles, said radially outermost circle having a center which is located within and closely adjacent to the pitch circle of said other rotor, said crest portion thereby projecting beyond said pitch circle of said other rotor a distance corresponding approximately to the radius of said outermost circle.
4 Assignments
0 Petitions
Accused Products
Abstract
The threads of the gate rotor of a screw rotor machine are generated by a rounded crest portion of the main rotor thread so that the flanks of the gate rotor threads will have a contour tangent to a plurality of circles which have progressively decreasing diameters taken from the radially innermost to the radially outermost of said circles, with the circles each having a center which lies on a curved radial line directed forwardly of the direction of rotation of the gate rotor when the machine is operated as a compressor. A crest portion of the gate rotor threads shaped in conformity with the radially outermost of said contour-defining plurality of circles has its center lying within and closely adjacent to the pitch circle of the gate rotor, with the gate rotor thread crest portion projecting beyond the gate rotor pitch circle a distance corresponding approximately to the radius of the radially outermost circle.
15 Citations
21 Claims
- 1. In a screw rotor machine including a housing defining a pair of intersecting parallel bores, and a pair of rotors mounted for rotation within said bores of said housing, said rotors having intermeshing helical threads and grooves, with the threads and grooves of one of said rotors lying substantially outside the pitch circle of said one rotor and with the threads and grooves of the other of said rotors lying substantially inside the pitch circle of said other rotor, said threads of said other rotor including a crest portion located substantially outside the pitch circle of said other rotor, with flanks of the threads of said other rotor defining, respectively, one side each of adjacent grooves located on opposite sides of said thread, one of said flanks of said threads of said other rotor operating to define the side of an adjacent groove which is the trailing side of said groove when said machine is operated as a compressor and the leading side when said machine is operated as a motor, said trailing side of said groove being substantially generated from a point in said groove closest to the axis of said other rotor to a point where said groove intersects the pitch circle of said other rotor by a crest portion of the respective thread of said one rotor which is radially most remote from the axis of said one rotor, the improvement which comprises that said radially remote crest portion of said one rotor is rounded with a relatively small radius dimension to generate the flanks of the threads of said other rotor to be tangent to a plurality of circles having centers which lie on a radial line which is curved in the direction of rotation of said other rotor, said circles having diameters which decrease taken from the radially innermost to the radially outermost of said circles, with said crest portion of said threads of said other rotor being shaped in conformity with the radially outermost of said plurality of circles, said radially outermost circle having a center which is located within and closely adjacent to the pitch circle of said other rotor, said crest portion thereby projecting beyond said pitch circle of said other rotor a distance corresponding approximately to the radius of said outermost circle.
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15. A screw rotor machine comprising:
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a housing defining a pair of intersecting parallel bores;
a main rotor and a gate rotor each defining a pitch circle and each being mounted for rotation, respectively, within said bores of said housing;intermeshing helical threads and grooves formed, respectively, on said main rotor and said gate rotor, said threads and grooves of said main rotor lying substantially outside said main rotor pitch circle, said threads and grooves of said gate rotor lying substantially inside said gate rotor pitch circle, said main rotor threads having opposed flanks formed with a generally convex profile, said gate rotor threads having opposed flanks formed with a generally concave profile; and a rounded crest portion on said main rotor threads generating said flanks of said gate rotor threads as tangents to a plurality of circles having progressively decreasing diameters taken from the radially innermost to the radially outermost of said plurality of circles; said circles having centers which lie on a curved radial line directed forwardly of the direction of rotation of said gate rotor when said machine is operated as a compressor. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification