High efficiency one-piece centrifugal blower

• US 6,755,615 B2
• Filed: 12/04/2001
• Issued: 06/29/2004
• Est. Priority Date: 12/04/2000
• Status: Active Grant

• Current Assignee: Robert Bosch Corporation (Robert Bosch GmbH)
• Original Assignee: Robert Bosch Corporation (Robert Bosch GmbH)
• Inventors: Chapman, Thomas
• Primary Examiner(s): VERDIER, CHRISTOPHER M
• Application Number:
  US10/005,031
• Publication Number:
  US 20020106277A1
• Time in Patent Office: 938 Days
• Field of Search: 415/206, 415/211.2, 415/213.1, 415/915, 416/185, 416/186.R, 416/187, 416/189, 416/192, 416/223.B, 416/241.A, 416/234, 417/423.1, 417/423.14
• US Class Current: 415/206
• CPC Class Codes: F04D 29/023 especially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/281 for fans or blowers
• CPC Class Codes: F04D 29/282 the leading edge of each vane being substantially parallel to the rotation axis
• CPC Class Codes: F04D 29/4233 with volutes extending mainly in axial or radially inward direction
• CPC Class Codes: F05D 2230/53 by integrally manufacturing a component, e.g. by milling from a billet or one piece construction

Abstract

The arrangement features a centrifugal impeller that exhibits relatively high operating efficiency and high pressure capability, and can be easily constructed as a single piece. The arrangement is useful where relatively high operating efficiency and low cost construction are required, and it is particularly suited for manufacture by injection molding plastic. The impeller is characterized by: a) a hub that extends to a radius less than that of the impeller inlet, allowing one piece construction by an injection molding tool with no slides or action; b) blades that extend from a radius less than the hub radius at the base of the blades, allowing the base of the blades to connect to the hub; c) an impeller top shroud that has curvature in a plane that contains the impeller axis; and d) a cylindrical area ratio between 1.0 and 2.0. The blower assembly is characterized by a separate base plate positioned in close proximity to the base of the impeller blades. The base plate can be incorporated into a motor flange or a blower or motor housing.

Claims

1. A centrifugal impeller mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

a) it is injection molded in one piece;

b) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

c) the blades extend outwardly from a radius less than the impeller hub radius;

d) the top shroud has curvature in a plane that contains the impeller axis;

e) the cylindrical area ratio is between 1.0 and 2.0; and

f) said minimum chord length is at least 15% of the impeller diameter.

4. The centrifugal impeller of claim 1, claim 2 or claim 3 further characterized in that said top shroud incorporates at least one ring for the control of flow recirculation.

5. The centrifugal impeller of claim 1, claim 2 or claim 3 further characterized in that said top shroud covers the blades over at least 50% of the radial extent of the blades that is greater than the impeller inlet radius.

6. The centrifugal impeller of claim 1, claim 2 or claim 3 further characterized in that the tops of the blade leading edges protrude inwardly to a radius less than the impeller inlet radius.

9. The centrifugal impeller of claim 1 further characterized in that said blade solidity is at least 2.0 and said blades make contact with the hub over less than 20% of the meanline length at the base of the blades.

10. The centrifugal impeller of claim 1, claim 2 or claim 3 further characterized in that the tops of the blade leading edges protrude inwardly to a radius 1-8 millimeters less than the impeller inlet radius.

11. The centrifugal impeller of claim 1, claim 2 or claim 3 further characterized in that the impeller has an inlet with an inlet area and an outlet with an outlet area, and the ratio of the inlet area to the outlet area is between 0.7 and 1.0.

12. A centrifugal blower assembly comprising a base plate and the impeller of claim 1, claim 2 or claim 3, said impeller top shroud and base plate together forming an airflow path from an inlet to an outlet;

said base plate being characterized in that;

1) it extends outwardly to a radius greater than the impeller hub radius;

2) it is non-rotating, and;

3) the clearance between the base plate and the impeller blades is less than 10 percent of the impeller radius.

13. The centrifugal blower assembly of claim 12 further comprising a blower housing and further characterized in that the base plate is integrated into a portion of said blower housing as a single monolithic part.

14. The centrifugal blower assembly of claim 12 further comprising a motor and a motor flange, further characterized in that the base plate is integrated into said flange as a single monolithic part.

15. The centrifugal blower assembly of claim 12 further comprising a motor housing and further characterized in that the base plate is integrated into said motor housing as a single monolithic part.

16. The centrifugal blower assembly of claim 15 further comprising a blower housing and further characterized in that the motor housing is integrated into a portion of said blower housing as a single monolithic part.

17. The centrifugal blower assembly of claim 12 further characterized in that said base plate is contoured in combination with said impeller to match the contour of the base of the impeller blades as the impeller rotates, establishing said airflow path.

18. The centrifugal blower assembly of claim 12 further characterized in that said base plate is curved in a plane that includes the fan axis.

19. A method of making the centrifugal impeller of claim 1claim 2 or claim 3 by injection-molding said impeller as a single piece.

20. A method of assembling the centrifugal blower assembly of claim 13 in which a motor is mounted to said portion of said blower housing, and said impeller is attached to said motor.

21. A method of assembling the centrifugal blower assembly of claim 14 in which said motor is mounted to said motor flange, and said impeller is attached to said motor.

22. A method of assembling the centrifugal blower assembly of claim 15 in which a motor is mounted to said motor housing, and said impeller is attached to said motor.

23. A method of assembling the centrifugal blower assembly of claim 16 in which a motor is mounted to said motor housing, and said impeller is attached to said motor.

26. A centrifugal blower assembly according to claim 15 which is sized and configured to be installed in an automotive climate control system.

27. A centrifugal blower assembly according to claim 16 which is sized and configured to be installed in an automotive climate control system.

2. A centrifugal impeller mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

a) it is injection molded in one piece;

b) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

c) the blades extend outwardly from a radius less than the impeller hub radius;

d) the top shroud has curvature in a plane that contains the impeller axis;

e) the cylindrical area ratio is between 1.0 and 2.0; and

f) said blade solidity is at least 2.0.

7. The centrifugal impeller of claim 2 or 3 further characterized in that said minimum chord length is at least 15% of the impeller diameter.

3. A centrifugal impeller mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

a) it is injection molded in one piece;

b) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

c) the blades extend outwardly from a radius less than the impeller hub radius;

d) the top shroud has curvature in a plane that contains the impeller axis;

e) the cylindrical area ratio is between 1.0 and 2.0; and

f) said blades make contact with the hub over less than 20% of the meanline length at the base of the blades.

8. The centrifugal impeller of claim 3 further characterized in that said blade solidity is at least 2.0.

24. A centrifugal blower assembly according to 13 which is sized and configured to be installed in an automotive climate control system.

25. A centrifugal blower assembly according to 14 which is sized and configured to be installed in an automotive climate control system.

28. A centrifugal blower assembly comprising a base plate and a centrifugal impeller;

A. said impeller being mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

1) it is injection molded in one piece;

2) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

3) the blades extend outwardly from a radius less than the impeller hub radius;

4) the top shroud has curvature in a plane that contains the impeller axis, and;

5) the cylindrical area ratio is between 1.0 and 2.0; and

B. said base plate being characterized in that;

1) it extends outwardly to a radius greater than the impeller hub radius;

2) it is non-rotating, and;

3) the clearance between the base plate and the impeller blades is less than 10 percent of the impeller radius,

said impeller top shroud and base plate together forming an airflow path from an inlet to an outlet,

said assembly further comprising a motor and a motor flange, said base plate being integrated into said flange as a single monolithic part.

36. The centrifugal blower assembly of claim 28, claim 29 or claim 31 further characterized in that said base plate is contoured in combination with said impeller to match the contour of the base of the impeller blades as the impeller rotates, establishing said airflow path.

37. A method of assembling the centrifugal blower assembly of claim 28 in which said motor is mounted to said motor flange, and said impeller is attached to said motor.

39. A centrifugal blower assembly according to claim 28, claim 29, claim 30 or claim 31 which is sized and configured to be installed in an automotive climate control system.

29. A centrifugal blower assembly comprising a base plate and a centrifugal impeller;

A. said impeller being mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

1) it is injection molded in one piece;

2) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

3) the blades extend outwardly from a radius less than the impeller hub radius;

4) the top shroud has curvature in a plane that contains the impeller axis, and;

5) the cylindrical area ratio is between 1.0 and 2.0; and

B. said base plate being characterized in that;

1) it extends outwardly to a radius greater than the impeller hub radius;

2) it is non-rotating, and;

3) the clearance between the base plate and the impeller blades is less than 10 percent of the impeller radius,

said impeller top shroud and base plate together forming an airflow path from an inlet to an outlet,

said assembly further comprising a motor housing and further characterized in that the base plate is integrated into said motor housing as a single monolithic part.

30. The centrifugal blower assembly of claim 29 further comprising a blower housing and further characterized in that the motor housing is integrated into a portion of said blower housing as a single monolithic part.

38. A method of assembling the centrifugal blower assembly of claim 29 or 30 in which a motor is mounted to said motor housing, and said impeller is attached to said motor.

31. A centrifugal blower assembly comprising a base plate and a centrifugal impeller;

A. said impeller being mounted to rotate on an axis, the impeller comprising a plurality of blades, each having a leading edge and a trailing edge, an impeller hub, and a top shroud;

the blades defining an impeller diameter, a cylindrical area ratio, a minimum chord length, a blade meanline length and a blade solidity; and

the top shroud forming an inlet to the impeller having an impeller inlet radius;

said impeller characterized in that;

1) it is injection molded in one piece;

2) the impeller hub extends outwardly to a radius less than that of the impeller inlet radius;

3) the blades extend outwardly from a radius less than the impeller hub radius;

4) the top shroud has curvature in a plane that contains the impeller axis, and;

5) the cylindrical area ratio is between 1.0 and 2.0; and

B. said base plate being characterized in that;

1) it extends outwardly to a radius greater than the impeller hub radius;

2) it is non-rotating;

3) the clearance between the base plate and the impeller blades is less than 10 percent of the impeller radius,

4) said base plate is curved in a plane that includes the fan axis

said impeller top shroud and base plate together forming an airflow path from an inlet to an outlet.

32. The centrifugal blower assembly of claim 31 further comprising a blower housing and further characterized in that the base plate is integrated into a portion of said blower housing as a single monolithic part.

33. The centrifugal blower assembly of claim 31 further comprising a motor and a motor flange, further characterized in that the base plate is integrated into said flange as a single monolithic part.

34. The centrifugal blower assembly of claim 31 further comprising a motor housing and further characterized in that the base plate is integrated into said motor housing as a single monolithic part.

35. The centrifugal blower assembly of claim 34 further comprising a blower housing and further characterized in that the motor housing is integrated into a portion of said blower housing as a single monolithic part.