US 6,599,112 B2 · Offset thread screw rotor device

Abstract

A screw rotor device has a housing with an inlet port and an outlet port, a male rotor, and a female rotor. The male rotor has a pair of helical threads with a phase-offset aspect, and the female rotor has a corresponding pair of helical grooves. The female rotor counter-rotates with respect to the male rotor and each of the helical grooves respectively intermeshes in phase with each of the helical threads. The phase-offset aspect of the helical threads is formed by a pair of teeth bounding a toothless sector. The arc angle of the toothless sector is a least twice the arc angle that subtends either one of the teeth. The helical grooves have a radially narrowing axial width at the periphery of the female rotor.

Drawings

Claims26

Dependent claims

A screw rotor device for positive displacement of a working fluid, comprising:

a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
a male rotor having at least one pair of phase-offset helical threads, wherein said male rotor is rotatably mounted about an axis between said first end and said second end of said housing and wherein a cross-section of said pair of phase-offset helical threads, in a plane perpendicular to said axis, comprises a first tooth, a second tooth and a toothless sector therebetween, said first tooth being subtended by a first arc angle with respect to said axis and said sector having a second arc angle that is at least twice said first arc angle, said first tooth and said second tooth having a profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing;
and
a female rotor having at least one pair of phase-offset helical grooves, wherein said female rotor counter-rotates with respect to said male rotor and each of said phase-offset helical grooves respectively intermeshes in phase with each of said phase-offset helical threads, said female rotor having a periphery in close tolerance with said housing.

1 more element

A screw rotor device for positive displacement of a working fluid, comprising:

a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
a female rotor rotatably mounted about an axis extending between said first end and said second end of said housing and having a helical groove with a radially narrowing axial width at a periphery of said female rotor, said periphery being in close tolerance with said housing;
and
a male rotor having a helical thread, wherein said male rotor counter-rotates with respect to said female rotor and said helical thread intermeshes with said helical groove, said helical thread having a cut-in convex profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing, wherein said minor diameter arc has a first arc angle and said tooth segment is subtended by a second arc angle greater than said first arc angle.

1 more element

A screw rotor device for compressing a gaseous working fluid, comprising:

a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
a male rotor having a first helical thread and a second helical thread adjacent said first helical thread, wherein said male rotor is rotatably mounted about an axis extending between said first end and said second end of said housing, said helical threads each having a profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing, wherein said profile is identically shaped in each plane perpendicular to said axis and passing through said male rotor at axial locations between said first end and said second end of said housing;
a female rotor having a first helical groove and a second helical groove, wherein said female rotor counter-rotates with respect to said male rotor and said first helical groove intermeshes with said first helical thread and said second helical groove intermeshes with said second helical thread, said female rotor having a periphery in close to tolerance with said housing;
and
a valve operatively communicating with said outlet port and contained within said housing, wherein the working fluid exiting the screw rotor device through said outlet port also passes through said valve, and wherein said valve is selected from the group consisting of a rotor-actuated valve and a pressure-actuated valve.

2 more elements

Dependencies are inferred from the claim text.

Description2,986 words

Summary601 words

#Not Applicable.

#1. Field of the Invention

#This invention relates generally to rotor devices and, more particularly to screw rotors.

Brief description of the drawings5 figures

#Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.

#The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings:

#FIG. 1 illustrates an axial cross-sectional view of a screw rotor device according to the present invention;

Detailed description2,228 words

#Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 illustrates an axial cross-sectional schematic view of a screw rotor device 10. The screw rotor device 10 generally includes a housing 12, a male rotor 14, and a female rotor 16. The housing 12 has an inlet port 18 and an outlet port 20. The inlet port 18 is preferably located at the gearing end 22 of the housing 12, and the outlet port 20 is located at the opposite end 24 of the housing 12. The male rotor 14 and female rotor 16 respectively rotate about a pair of substantially parallel axes 26, 28 within a pair of cylindrical bores 30, 32 extending between ends 22, 24.

#In the preferred embodiment, the male rotor 14 has at least one pair of helical threads 34, 36, and the female rotor 16 has a corresponding pair of helical grooves 38, 40. The female rotor 16 counter-rotates with respect to the male rotor 14 and each of the helical grooves 38, 40 respectively intermeshes in phase with each of the helical threads 34, 36. In this manner, the working fluid flows through the inlet port 18 and into the screw rotor device 10 in the spaces 39, 41 bounded by each of the helical threads 34,36, the female rotor 16, and the cylindrical bore 30 around the male rotor 14. The spaces 39, 41 are closed off from the inlet port 18 as the helical threads 34, 36 and helical grooves 38, 40 intermesh at the inlet port 18. As the female rotor 16 and the male rotor 14 continue to counter-rotate, the working fluid is positively displaced toward the outlet port 20.

#The pair of helical threads 34, 36 have a phase-offset aspect that is particularly described in reference to FIGS. 2 and 3 which show the cross-sectional profile of the screw rotor device through line 2—2, the two-dimensional profile being represented in the plane perpendicular to the axes of rotation 26, 28. The cross-section of the pair of helical threads 34, 36 includes a pair of corresponding teeth 42, 44 bounding a toothless sector 46. The phase-offset of the helical threads 34, 36 is defined by the arc angle β subtending the toothless sector 46 which depends on the arc angle α of either one of the teeth 42, 44. In particular, for phase-offset helical threads, the toothless sector 46 must have an arc angle β that is at least twice the arc angle a subtending either one of the teeth 42, 44. The phase-offset relationship between arc angle β and arc angle α is particularly defined by equation (1) below: Arc ⁢ ⁢ Angle ⁢ ⁢ β ≥ 2 * Arc ⁢ ⁢ Angle ⁢ ⁢ α ( 1 )

Facts

Application

10/013,747Filed 19 Oct 2001

Published

US 2003/0077197 A124 Apr 2003

Granted

29 Jul 2003

Term ended

19 Oct 2021

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification3 codes

F01C 1/16
With toothed rotary pistons: with helical teeth, e.g. chevron-shaped, screw type
F01C 1/084
Details specially related to intermeshing engagement type machines or engines: toothed wheels
F01C
Rotary-piston or oscillating-piston machines or engines

Offset thread screw rotor device

Life of this patent

Offset thread screw rotor device

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims26

Description2,986 words

Drawings

Classification3 codes

Life of this patent

Description2,986 words