ROOTS TYPE FLUID MACHINE

• US 20070148030A1
• Filed: 12/08/2006
• Published: 06/28/2007
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toyota Jidoshokki
• Original Assignee: Kabushiki Kaisha Toyota Jidoshokki
• Inventors: Fujii, Toshiro, Hirano, Takayuki, Yamada, Kazuho
• Granted Patent: US 7,320,579 B2
• Time in Patent Office: Days
• US Class Current: 418/206.100
• CPC Class Codes: F04C 18/084 Toothed wheels
• CPC Class Codes: F04C 18/126 with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type

Abstract

A roots type fluid machine includes a housing, a pair of parallel rotary shafts and two-lobe rotors. Each rotor includes two lobe portions and two well portions. Each lobe portion has a profile of convex arc with a radius R and each well portion has a profile of concave arc which is an envelope of the convex arc of the lobe portion. The rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs. The base radius r is set in a range L/(2√{square root over ( )}2)<r<0.3(√{square root over ( )}2)L where distance between axes of the rotary shafts is L, and the radius R is set in a range {(√{square root over ( )}2)/16}πL<R<{(27−5√{square root over ( )}2)/56}L.

Claims

1. A roots type fluid machine comprising:

a housing;

a pair of parallel rotary shafts rotatably supported by the housing;

a two-lobe rotor disposed on each rotary shaft in a rotor chamber of the housing so that the rotors engage with each other, each of the rotors comprising;

two lobe portions each having a profile of convex arc with a radius R; and

two well portions each having a profile of concave arc which is an envelope of the convex arc of the lobe portion,

wherein the rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs,

wherein the base radius r is set in a range L/(2√

{square root over ( )}2)<

r<

0.3(√

{square root over ( )}2)L where distance between axes of the rotary shafts is L, and the radius R is set in a range {(√

{square root over ( )}2)/16}π

L<

R<

{(27−

5√

{square root over ( )}2)/56}L.

2. The roots type fluid machine according to claim 1, wherein the rotary shafts include a drive shaft and a driven shaft, and the rotors include a drive rotor and a driven rotor.

3. The roots type fluid machine according to claim 1, wherein the rotors are fixedly mounted on the rotary shafts.

4. The roots type fluid machine according to claim 1, wherein the roots type fluid machine is a roots compressor.

5. A two-lobe rotor for use in a roots type fluid machine which includes a housing and a pair of parallel rotary shafts rotatably supported by the housing, the rotor being disposed on each rotary shaft in a rotor chamber of the housing so that the rotors engage with each other, each of the rotors comprising:

two lobe portions each having a profile of convex arc with a radius R; and

two well portions each having a profile of concave arc which is an envelope of the convex arc of the lobe portion,

wherein the rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs,

wherein the base radius r is set in a range L/(2√

{square root over ( )}2)<

r<

0.3(√

{square root over ( )}2)L where distance between axes of the rotary shafts is L, and the radius R is set in a range {(√

{square root over ( )}2)/16}π

L<

R<

{(27−

5√

{square root over ( )}2)/56}L.

6. A roots type fluid machine comprising:

a housing;

a pair of parallel rotary shafts rotatably supported by the housing;

a three-lobe rotor disposed on each rotary shaft in a rotor chamber of the housing so that the rotors engage with each other, each of the rotors comprising;

three lobe portions each having a profile of convex arc with a radius R; and

three well portions each having a profile of concave arc which is an envelope of the convex arc of the lobe portion,

wherein the rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs,

wherein the base radius r is set in a range L/(2√

{square root over ( )}2)<

r<

1.35L where distance between axes of the rotary shafts is L, and the radius R is set in a range π

/(12√

{square root over ( )}2)L<

R<

0.25L.

7. The roots type fluid machine according to claim 6, wherein the rotary shafts include a drive shaft and a driven shaft, and the rotors include a drive rotor and a driven rotor.

8. The roots type fluid machine according to claim 6, wherein the rotors are fixedly mounted on the rotary shafts.

9. The roots type fluid machine according to claim 6, wherein the roots type fluid machine is a roots compressor.

10. A three-lobe rotor for use in a roots type fluid machine which includes a housing and a pair of parallel rotary shafts rotatably supported by the housing, the rotor being disposed on each rotary shaft in a rotor chamber of the housing so that the rotors engage with each other, each of the rotors comprising:

three lobe portions each having a profile of convex arc with a radius R; and

three well portions each having a profile of concave arc which is an envelope of the convex arc of the lobe portion,

wherein the rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs,

wherein the base radius r is set in a range L/(2√

{square root over ( )}2)<

r<

1.35L where distance between axes of the rotary shafts is L, and the radius R is set in a range π

/(12√

{square root over ( )}2)L<

R<

0.25L.