Rotary pump with a fixed shaft

• US 20100158725A1
• Filed: 12/15/2009
• Published: 06/24/2010
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: Buhler Motor GmbH
• Original Assignee: Buhler Motor GmbH
• Inventors: French, Colin Richard, Werson, Michael John
• Granted Patent: US 8,303,268 B2
• Time in Patent Office: Days
• US Class Current: 417/423.120
• CPC Class Codes: F04D 13/026 Details of the bearings
• CPC Class Codes: F04D 13/027 Details of the magnetic circuit
• CPC Class Codes: F04D 13/0633 Details of the bearings
• CPC Class Codes: F04D 13/0646 the hollow pump or motor shaft being the conduit for the working fluid
• CPC Class Codes: F04D 13/0666 the motor being of the plane gap type
• CPC Class Codes: F04D 29/0413 hydrostatic; hydrodynamic thrust bearings
• CPC Class Codes: F04D 29/043 Shafts
• CPC Class Codes: F04D 29/047 hydrostatic; hydrodynamic
• CPC Class Codes: F04D 29/58 Cooling of machines or engines in general F01P; Heating; Diminishing heat transfer for the motor of air-pump units F04D25/082; cooling of shafts or bearings F04D29/04
• CPC Class Codes: F05D 2240/61 Hollow
• CPC Class Codes: Y10T 29/49245 Vane type or other rotary, e.g., fan

Abstract

A rotary pump (1) with a multipart pump housing (4), comprising a suction connector (6) and a pressure connector (7), a pump impeller (5) mounted on a fixed shaft (3), the pump rotor (5) being designed as a permanent magnetic rotor cooperating with an electromagnetic stator. The task of the invention in a rotary pump is to achieve excellent efficiency in a compact design. The rotary pump is also supposed to guarantee high lifetime and improved heat removal. This task is solved according to the invention in that the shaft (3) is firmly connected to a first pump housing (2), referred to as pump head, which includes the suction connector (6) or is connected to it, the shaft (3) forming an axis of symmetry to an inside wall area of pump head (2).

Claims

1. A rotary pump driven by an electric motor with a stator, the rotary pump comprising:

a multipart pump housing having a first pump housing part defining a pump head with an inside wall area;

a pressure connector connected to the first housing part;

a suction connector connected to the pump head;

a fixed shaft connected to the stator, the fixed shaft forming an axis of symmetry to the inside wall area of the pump head; and

a permanent magnetic pump impeller rotatably mounted on the fixed shaft.

2. The rotary pump according to claim 1, wherein the shaft is fastened exclusively in the pump head.

3. The rotary pump according to claim 1, further comprising means for exclusively supporting the shaft in the pump head or parts fastened to the pump head.

4. The rotary pump according to claim 1, further comprising a mounting pin in the pump head wherein the shaft is connected in shape-mated fashion to the mounting pin.

5. The rotary pump according to claim 1, wherein the fixed shaft is partially hollow.

6. The rotary pump according to claim 1, wherein the fixed shaft is hollow over its entire length.

7. The rotary pump according to claim 1, wherein the shaft consists of a ceramic material.

8. The rotary pump according to claim 1, wherein a first axial bearing ring is arranged on the fixed shaft for axial bearing of the pump impeller.

9. The rotary pump according to claim 1, wherein a first axial bearing ring is arranged in the pump head for axial bearing of the pump impeller.

10. The rotary pump according to claim 8, wherein a second axial bearing ring is accommodated in a heat-conducting element in the pump housing.

11. The rotary pump according claim 10, wherein a bearing support ring is arranged between the axial bearing ring (8) and the heat-conducting element.

12. The rotary pump according to claim 10, wherein the pump impeller is arranged and mounted to freely rotate between the first and second axial bearing rings.

13. The rotary pump according to claim 11, wherein the pump impeller has a hollow cylindrical fixed bearing, having sliding surfaces on both ends, with which it can be supported on the first and second axial bearing rings.

14. The rotary pump according to claim 1, wherein the heat-conducting element protrudes into a pump space defined in the pump housing.

15. The rotary pump according to claim 1, wherein a significant part of the fixed shaft extends freely into a cavity bounded by the heat-conducting element.

16. The rotary pump according to claim 15, wherein the section of the fixed shaft extending freely into the cavity occupies 20-60% of the total length of the fixed shaft.

17. The rotary pump according to claim 1, further comprising:

a first axial bearing ring is arranged on the fixed shaft for axial bearing of the pump impeller;

a second axial bearing ring is arranged on the fixed shaft for axial bearing;

a second pump housing part forming part of the multipart pump housing;

an air gap formed between the pump impeller and the split plate;

a cavity defined in the pump housing for receiving a portion of the fixed shaft;

a flow channel defined in the fixed shaft; and

a mounting pin receiving a portion of the fixed shaft, the mounting pin having a passage in communication with the flow channel, wherein part of a feed medium can be guided back into a main hydraulic circuit via a closed path from a pressure area of the pump via the air gap, an intermediate space between the second axial bearing ring and the fixed shaft, the cavity, the flow channel and the passage.

18. A method for production of a pump head of the rotary pump of claim 1, the method comprising the steps of:

inserting the fixed shaft into an injection molding die used to form the pump head; and

deforming the pump head with precise alignment of the fixed shaft to the inside wall area of pump head.

19. A method for production of a pump head of the rotary pump of claim 8, the method comprising the steps of:

inserting the fixed shaft and the first axial bearing ring into an injection molding die used to form the pump head; and

deforming the pump head with precise alignment of the fixed shaft to the inside wall area of pump head.

20. A method for production of a pump head of the rotary pump of claim 1, the method comprising the steps of press-fitting the shaft into the pump head.