ARRANGEMENT FOR DELIVERING FLUIDS
An arrangement for delivering fluids has a fluid pump having a pump wheel (90), which wheel is joined to a first permanent magnet (92). The pump wheel (90) is rotatably arranged inside a liquid-tight pump housing (80, 82, 84, 86, 88). This housing is shaped, near the first permanent magnet (92), as a partitioning can (80, 82). The arrangement also has an electronically commutated electric motor (20) having a stator (22) and a rotor (26) arranged rotatably relative thereto, which rotor comprises a second permanent magnet (67) that coacts with the first permanent magnet (92) to act as a magnetic coupling (94). Arranged in the space between the second permanent magnet (67) and partitioning can (80, 82) is a plurality of soft ferromagnetic magnetic flux conductors (150).
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This application is a section 371 of PCT/EP05/08668, filed 10 Aug. 2005 and published 13 Apr. 2006 as WO 2006-37396-A.
FIELD OF THE INVENTIONThe invention relates to an arrangement for pumping fluids. As fluids, liquid and/or gaseous media can be pumped.
BACKGROUNDIn computers, components having high heat flux densities (e.g. 60 W/cm2) are in use today. The heat from these components must first be transferred into a liquid circulation system, and from that circulation system the heat must be discharged to the ambient air via a liquid/air heat exchanger.
Dissipation of heat from components having a high heat flux density is accomplished by means of so-called heat absorbers or cold plates. In these, heat is transferred to a cooling liquid, and the latter is usually caused to circulate in a circulation system.
In this context, the cooling liquid flows not only through the heat absorber but also through a liquid pump that produces the forced circulation and produces an appropriate pressure buildup and appropriate volumetric flow through the heat absorber and an associated heat exchanger, so that the heat transfer coefficients relevant to these heat-transfer elements become large and the temperature gradients necessary for heat transfer become small.
A fan is usually arranged near the heat exchanger, which fan produces, on the air side of the heat exchanger, a forced convection of the cooling air as well as good transfer coefficients.
In cooling arrangements of this kind, the fan and the liquid pump are driven separately, and these components are also often physically separate from one another. Two drives are therefore required, which in most cases operate rotationally. These drives require energy and also a fairly large installation space, both of which are undesirable.
SUMMARY OF THE INVENTIONIt is therefore an object of the invention to make available a novel arrangement for delivering fluids.
According to the invention, this object is achieved by using soft ferromagnetic flux conductors to assist in magnetically coupling an electric motor to a pump rotor across a partitioning can which separates them.
A very compact arrangement with good efficiency is thereby obtained, in which context the soft ferromagnetic magnetic flux conductors bridge the space between the partitioning can and the second permanent magnet and thereby make possible a greater distance between the first permanent magnet and second permanent magnet of the magnetic coupling.
Further details and advantageous refinements of the invention will be evident from the exemplifying embodiments, in no way to be understood as a limitation of the invention, that are described below and depicted in the drawings.
In the description that follows, the terms “left,” “right,” “top,” and “bottom” refer to the respective Figure of the drawings. Identical or identically functioning parts are labeled in the various Figures with the same reference characters, with an apostrophe added if applicable, e.g. 150 and 150′.
Internal stator 22 is mounted, usually by being pressed on, on a bearing tube 30 made of a suitable plastic. The shape of bearing tube 30 is particularly clearly evident from
External rotor 26 has a design with a so-called rotor cup 40, which is implemented here as a deep-drawn cup-shaped sheet-metal part made of soft ferromagnetic material. Ring magnet 36 is mounted in this sheet-metal part 40 so that the latter forms a magnetic yoke for rotor magnet 36.
Sheet-metal part 40 is mounted on a hub 44 in which a shaft 46 is mounted in the manner depicted. Shaft 46 is journaled in two ball bearings 48, 50 whose outer rings are held at a distance from one another by a spacing element 52 (cf. the schematic depictions in
This assembly procedure makes it possible, in the context of
The outer side of sheet-metal part 40 is surrounded by a plastic part 63 in which fan blades 64 are formed, in the manner depicted, by plastic injection molding. These blades rotate, during operation, in an opening 66 of a fan housing 68 (cf.
Bearing tube 30 transitions to the right in
Pump wheel 90 is preferably implemented integrally with a permanent-magnet rotor 92 that, with permanent magnet 67, forms a magnetic coupling 94; i.e., when permanent magnet 67 rotates, permanent magnet 92 also rotates and thereby drives delivery wheel 90, with the result that the latter draws in liquid via inlet 96 and pumps it out via an outlet 98, as indicated by arrows. Any desired other hydraulic machine, e.g. a compressor for a refrigerant, can of course also be provided instead of a spiral pump.
As is apparent from the drawings, the distance from permanent magnet 67 to permanent magnet 92 is large, so that a direct transfer of torque between these two magnets would not be possible. For this reason, a plurality of magnetic flux conductors in the form of flux-conducting elements 150 is arranged between magnets 67, 92, which elements map the magnetic field of the rotating permanent magnet 67 onto partitioning tube 82 and thereby produce a rotation of permanent magnet 92.
Accordingly, south poles S are also constituted at the inner end (viewed radially) of flux-conducting elements 150 to the left of pole boundary 156, which poles attract the north pole N of permanent magnet 92.
To the right of pole boundary 156, flux-conducting elements 150 are located opposite north poles N, and north poles N that attract a south pole of permanent magnet 92 are accordingly located at the radially inner ends of flux-conducting elements 150 there.
When external magnet 67 rotates clockwise, as depicted in
Flux-conducting elements 150 therefore bridge the distance between magnets 67 and 92, so that magnet 92 can have a small diameter. This is important because magnet 92 rotates in the cooling liquid, and consequently, if the diameter of magnet 92 is small, the frictional losses produced in that cooling liquid are low. This contributes to good efficiency for the arrangement.
Permanent magnet 92 of the fluid pump is rotatably journaled by means of a plain bearing 100 on a stationary shaft 106 that is mounted in liquid-tight fashion, in the manner depicted, in a rightward-protruding projection 107 of portion 80. A snap ring (not depicted) can be provided at the right end of shaft 106. Magnet 92 is attracted by the adjacent flux-conducting elements 150 and retained in the axial position depicted.
For the mounting procedure depicted for bearings 48, 50, an open space 109 is required between the right end (in
Cylindrical portion 86 is joined via radially extending struts 114 to fan housing 68, so that the latter, with partitioning tube 82, portion 80, and bearing tube 30, forms a one-piece plastic part; this simplifies assembly of the arrangement, minimizes the number of parts, and reliably separates from one another the units being used, so that liquid cannot travel from hydraulic machine 90 to electric motor 20 and damage it. Stationary shaft 106 likewise forms a constituent of this injection-molded part, since it is anchored therein during manufacture, and therefore likewise contributes to the compact design.
Manner of OperationIn operation, external-rotor motor 20 drives external rotor 26 so that fan blades 64 rotate in housing 68 and thereby generate an air flow therein. Alternatively, the fan can also be implemented as a diagonal or radial fan. An axial fan is depicted.
At the same time, ring magnet 67 drives rotor magnet 92 via flux-conducting elements 150 and through partitioning tube 82, thus rotating pump wheel 90 so that the latter draws in liquid through inlet 96 and pumps it out through outlet 98. A pump of this kind can be used, for example, in a fountain in order to draw in water and pump it out, or to pump blood in a heart-lung machine, or to transport cooling liquid in a closed cooling circuit, in which case pump wheel 90 then has the function of a circulating pump.
Because cover 88 is joined in liquid-tight fashion to cylindrical part 86, e.g. by laser welding, no liquid can escape to the outside from housing 88. Contributing to this is the fact that portion 80 and its projection 107 are free of any kind of orifices. This is possible because rotor 26 is very easy to install, for example, in the manner described below in the context of
As an alternative to
According to
Beginning at projection 56, the first is compression spring 58, whose larger-diameter end rests in a depression 39. This spring is followed by the annular retaining member in the form of retaining washer 54. Spring 58 does not abut against retaining member 54.
Retaining member 54 is followed by rolling bearing 48, with its outer ring 48e and its inner ring 48i. The latter is displaceable in an axial direction on shaft 46. The lower end of spring 58 abuts against the upper end of inner ring 48i. Rolling bearing 48 is followed by spacing element 52, which is guided displaceably on shaft 46 by means of a radially inwardly protruding projection 53, and whose upper end, as depicted, abuts against the lower end of outer ring 48e.
Spacing element 52 is followed by lower rolling bearing 50, with its outer ring 50e that abuts with its upper end against spacing element 52, and with its inner ring 50i that is axially displaceable on shaft 46 and abuts with its lower end against snap ring 59 when the assembling of motor 20 is finished.
As is readily apparent, it is possible, by pushing upward on lower rolling bearing 50 with a force F, to compress spring 58 and thereby to displace the two bearings 48, 50, spacing element 52, and retaining washer 54 upward on shaft 46, so that inner ring 50i no longer abuts against snap ring 59 but instead ends up at a distance therefrom. In this case projection 56 of rotor 22 comes into contact against retaining washer 54 and makes it possible, by way thereof, to transfer an axial force to retaining washer 54, outer ring 48e, spacing element 52, and outer ring 50e when rotor 26 is pressed downward with a force K during assembly.
In this context, a force K is applied to rotor 26 in the axial direction; and because outer rings 48e, 50e of rolling bearings 48, 50 are pressed with a press fit into bearing tube 30, spring 58 is compressed by force K so that shaft 46 is displaced in ball bearings 48, 50, and projection 56 acts via retaining washer 54 on outer ring 48e of ball bearing 48 and also via spacing element 52 on outer ring 50e of ball bearing 50, and thus presses the two ball bearings 48, 50 into bearing tube 30.
Pressing-in continues until outer ring 50e of the lower ball bearing 50 abuts against the upper end of ribs 83 that are provided in bearing tube 30 at its inner end 60.
According to
Force K is removed after pressing-in is complete, and what then results is the situation according to
Ring 160 is provided, on its lower side (in
Partitioning tube 82 can have a thinner wall thickness in this case.
As is clearly apparent to one skilled in the art from
Numerous variants and modifications are of course possible within the scope of the present invention.
Claims
1. An arrangement for pumping fluids, which comprises:
- a fluid pump having a pump wheel (90), which wheel is joined to a first permanent magnet (92), which pump wheel (90) is rotatably arranged inside a liquid-tight pump housing (80, 82, 84, 86, 88), which housing (80, 82, 84, 86, 88) is implemented, adjacent said first permanent magnet (92), as a partitioning can (80, 82);
- an electronically commutated electric motor (20) having a stator (22) and a rotor (26) arranged rotatably relative thereto, which rotor comprises a second permanent magnet (67) that coacts with the first permanent magnet (92) to act as a magnetic coupling (94);
- and a plurality of soft ferromagnetic magnetic flux conductors (150; 150′; 150″) arranged in the space between the second permanent magnet (67) and the partitioning can (80, 82), which conductors are arranged at a distance from one another in such a way that they map the magnetic field of the second permanent magnet (67), which field is effective at their end facing away from the partitioning can (80, 82), onto a region of the partitioning can (80, 82) associated with the first permanent magnet (92).
2. The arrangement according to claim 1, wherein
- the soft ferromagnetic magnetic flux conductors (150; 150′; 150″) are implemented as elements made of soft ferromagnetic material, which are arranged in a star configuration around the partitioning can (80, 82).
3. The arrangement according to claim 2, wherein
- the elements (150; 150′; 150″) are implemented in substantially plate-shaped fashion from soft ferromagnetic material.
4. The arrangement according to claim 1,
- wherein
- the soft ferromagnetic magnetic flux conductors (150; 150′; 150″) are implemented in the manner of flux concentrators.
5. The arrangement according to claim 1, wherein
- the electronically commutated electric motor is implemented as an external-rotor motor (20) having a rotor cup (63), inside which cup are arranged the rotor magnet (36) of the motor (20) and the second permanent magnet (67).
6. The arrangement according to claim 1, wherein
- a bearing element (106) for the pump wheel (90) is arranged inside the partitioning can (80, 82) on the latter, and
- a bearing element (30) for the rotor (26) of the electronically commutated electric motor (20) is arranged outside the partitioning can (80, 82) on the latter.
7. The arrangement according to claim 6, wherein
- the bearing element for the rotor (26) of the electric motor (20) comprises a bearing tube (30) that is fixedly connected to the partitioning can (80, 82).
8. The arrangement according to claim 7, wherein
- the bearing tube (30) is integrally formed with the partitioning can (80, 82).
9. The arrangement according to claim 1, wherein fan blades (64) are joined to the rotor (26) of the electric motor (20).
10. The arrangement according to claim 9, wherein
- the permanent magnet of the rotor comprises a yoke that is implemented as a cup-like part (40), and the fan blades (64) are arranged on this cup-like part (40).
11. The arrangement according to claim 9, wherein the fan blades (64) are implemented as part of an axial fan wheel.
12. The arrangement according to claim 9, wherein
- the fan blades are implemented as part of a diagonal fan wheel.
13. The arrangement according to claim 9, wherein
- the fan blades are implemented as part of a radial fan wheel.
14. The arrangement according to claim 1, further comprising
- an air-directing housing (68) is joined to the partitioning can (80, 82).
15. The arrangement according to claim 14, wherein
- the air-directing housing (68) is implemented as a plastic part integral with the partitioning can (80, 82).
16. The arrangement according to claim 15, wherein
- the partitioning can (80, 82) is joined to the air-directing housing (68) via at least one strut (114).
17. The arrangement according to claim 7, wherein
- the electric motor is implemented as an external-rotor motor (20); and
- the internal stator (92) of said motor is mounted on the bearing tube (30), which tube serves for journaling of the rotor (26).
18. The arrangement according to claim 1, wherein
- the soft ferromagnetic magnetic flux conductors (150; 150′; 150″) are joined at their radially inner end regions to a support part (160) made of non-ferromagnetic material.
19. The arrangement according to claim 18, wherein the support part (160) is arranged on the partitioning can (80, 82).
20. The arrangement according to claim 19, wherein
- the partitioning can (80, 82) has an approximately cylindrical periphery; and
- the support part (160) is arranged on said periphery.
21. The arrangement according to claim 18, wherein
- the support part (160) is formed of plastic material, and is equipped with axial projections (168; 174) that are joined by means of a welding operation to an adjacent plastic part of the arrangement.
22. The arrangement according to claim 21, wherein
- the welded join is implemented by ultrasonic welding (170) at one axial end of the support part (160).
23. The arrangement according to claim 1,
- wherein
- the cross section of soft ferromagnetic magnetic flux conductors (150″) inside the support part (160) is enlarged (180), at least locally, in order to produce good anchoring of said conductors (150″) in the support part.
Type: Application
Filed: Aug 10, 2005
Publication Date: Jan 22, 2009
Applicant:
Inventors: Alexander Jordan (Pfalzrafenweiler), Michael Burgert (Freiburg)
Application Number: 11/576,688
International Classification: F04D 13/02 (20060101);