EP1778981A1

EP1778981A1 - Assembly for transporting fluid

Info

Publication number: EP1778981A1
Application number: EP05778381A
Authority: EP
Inventors: Hansjörg BERROTH
Original assignee: Ebm Papst St Georgen GmbH and Co KG
Current assignee: Ebm Papst St Georgen GmbH and Co KG
Priority date: 2004-10-07
Filing date: 2005-09-02
Publication date: 2007-05-02
Anticipated expiration: 2025-09-02
Also published as: US7780422B2; EP1778981B1; WO2006039965A1; DE502005005904D1; ATE413532T1; US20080038126A1; ES2315908T3

Abstract

An arrangement for pumping fluids has an electronically commutated external-rotor motor. The latter has a stator arranged on a stator carrier and a rotor joined to a first permanent magnet, which rotor is rotatably journaled, in a bearing tube, with respect to the stator. This bearing tube is arranged, at least partly, radially inside the stator carrier. The first permanent magnet is arranged in an annular interstice between the stator carrier and the bearing tube. A fluid pump has a pump wheel arranged rotatably inside a pump housing, which wheel is joined to a second permanent magnet, a liquid-tight but magnetically transparent partition being provided between the first permanent magnet and the second permanent magnet. This keeps fluid away from the motor wiring. The first permanent magnet forms, by coaction with the second permanent magnet, a magnetic coupling to the fluid pump, which magnetic coupling automatically produces a rotation of the pump wheel as a result of rotation of the motor rotor.

Description

Arrangement for conveying fluids

The invention relates to an arrangement for conveying fluids. As fluids liquid and / or gaseous media can be promoted.

In computers today components with high heat flux densities are used, for example 60 W / cm ² . These components must be cooled with suitable cooling arrangements to prevent thermal destruction of the components.

In such cooling arrangements, the dissipation of heat from these components takes place by means of so-called heat receivers or CoId plates. In these, the heat is transferred to a cooling liquid, which is usually placed in forced circulation in a liquid circuit. In this case, the cooling liquid flows through not only the heat absorber, but also a liquid pump, which causes the forced circulation and causes an adequate pressure build-up and an adequate volume flow through the heat absorber and an associated liquid-air heat exchanger. The liquid-to-air heat exchanger serves to release the heat from the cooling liquid to the ambient air. For this purpose, a fan is usually arranged in the liquid-air heat exchanger, which causes a forced convection of the cooling air and good transfer coefficients on the air side of the heat exchanger.

Due to the limited space available in computers and thus the high density of integration of components arranged therein, a compact design is desirable in such cooling arrangements.

It is therefore an object of the present invention to provide a novel fluid delivery system. This object is solved by the subject matter of the independent claims. Preferred embodiments are the subject of the dependent claims.

In particular, the object of the present invention is achieved by an arrangement according to claim 1. Accordingly, an arrangement according to the invention for conveying fluids comprises an electronically commutated external rotor motor with a stator arranged on a stator carrier and a rotor mounted in a bearing tube, and a fluid pump with a delivery wheel. The rotor of the electronically commutated external rotor motor and the delivery wheel of the fluid pump are magnetically coupled to each other via a magnetic coupling such that rotation of the rotor causes rotation of the delivery wheel. This magnetic coupling is formed by a first permanent magnet connected to the rotor in cooperation with a second permanent magnet connected to the impeller. Here, at least the first permanent magnet is disposed in a space between the stator and the bearing tube and separated from the second permanent magnet by a liquid-tight but magnetically transparent partition.

This gives a very compact arrangement with a high degree of integration and good efficiency, especially at low and medium speeds, the placement of the first permanent magnet in the space between the stator and the bearing tube allows the realization of a low height.

A preferred development of the arrangement according to the invention is the subject of claim 2. Accordingly, the second permanent magnet can also be arranged in the intermediate space between the stator and the bearing tube. This allows a further reduction in the height and an increase in the integrity of the unit external rotor motor, magnetic coupling and fluid pump.

A further preferred embodiment of the arrangement according to the invention is the subject of claim 10. Accordingly, the bearing tube, the partition and the stator can be formed as a one-piece, meandering in cross-section part. This allows a minimization of the number of parts and thus a simplified assembly of the arrangement.

Further details and advantageous developments of the invention will become apparent from the hereinafter described and illustrated in the drawings, in no way as a limitation of the invention to be understood embodiments. It shows:

1 shows a longitudinal section through a first preferred embodiment of an arrangement for conveying fluids according to the invention,

2 is an exploded view of the arrangement of FIG. 1, 3 is a sectional view of a three-dimensional view of a second preferred embodiment of an arrangement for conveying fluids according to the invention,

Fig. 4 is a longitudinal section through the arrangement of FIG. 3, and

5 is an exploded view of the arrangement of FIG .. 3

In the following description, the terms left, right, up and down refer to the respective drawing figure, and may vary from one drawing figure to the next, depending on a particular orientation (portrait or landscape). Identical or equivalent parts are denoted by the same reference numerals in the various figures and usually described only once.

1 shows an enlarged sectional view of a first embodiment of an arrangement with a fluid pump 84, which is exemplified as a centrifugal pump, and an electronically commutated external rotor motor 20. This has an internal stator 22 of conventional design, as shown by way of example in Fig. 2, eg a stator with salient poles or a claw-pole stator, and this is separated from a permanent-magnetic outer rotor 26 by a substantially cylindrical air gap 24. In operation, the outer rotor 26 rotates about the inner stator 22, which is why such motors 20 are referred to as external rotor motors.

The inner stator 22 is mounted on an annular stator support 34, usually by pressing. The shape of the stator carrier 34 is particularly clear from FIG. Below the inner stator 22 is located in Fig. 1, a circuit board 32. On this are, for example. (not shown here) electronic components, which are required for electronic commutation of the motor 20. Further, a rotor position sensor 38 is disposed on the circuit board 32, which is controlled by the rotor magnet 36 of the outer rotor 26. This rotor magnet 36 is designed as a permanent magnet ring and preferably has plastic-bonded magnetic material. Furthermore, the rotor magnet 36 is radially magnetized and preferably formed eight-pole. Its magnetization, that is, the distribution of its magnetic flux density, may be e.g. be rectangular or trapezoidal. The rotor position sensor 38 is controlled by a stray field of the rotor magnet 36, which allows a non-contact detection of the position of the outer rotor 26.

The outer rotor 26 has a construction with a so-called rotor bell 40, which is shown in Fig. 1 by way of example as a deep-drawn, cup-shaped sheet metal part and, for example a soft ferromagnetic material is formed. The rotor magnet 36 is fixed in this rotor bell 40, so that the latter forms a magnetic return for the rotor magnet 36.

On the outside of the rotor bell 40 fan blades 64 are exemplified. For this purpose, the rotor bell 40 is preferably surrounded by a plastic part (not shown), cf. Fig. 5, on which these fan blades 64 are formed by plastic injection molding in the manner shown. The fan blades 64 rotate during operation in a recess of a fan housing. A corresponding fan housing will be explained below with reference to FIG.

In the rotor bell 40, a shaft 46 is fixed in the manner shown. The shaft 46 is mounted in two ball bearings 48, 50, which are e.g. be pressed together with the shaft 46 from above into a bearing tube 30 during assembly in Fig. 1. The ball bearings 48, 50 can be held in the bearing tube by suitable retaining elements, e.g. a locking member. In the ball bearings 48, 50 pressed into the bearing tube 30, the shaft 46 can also be held by suitable holding elements, e.g. through a snap ring.

The assembly of the shaft 46 with the ball bearings 48, 50 in the bearing tube 30 is particularly clear from Fig. 2. Naturally, this assembly can be done in many ways and is therefore not limited to a specific type of mounting. It is noted, however, that the manner of mounting described in FIG. 1 makes it possible to mount the shaft 46 of the outer rotor 26 together with the completely pre-assembled ball bearings 48, 50 from above in the bearing tube 30, so that the end 60 shown in FIG the inner recess of the bearing tube 30 may be closed liquid-tight, see. For this purpose Fig. 2.

Between the bearing tube 30 and the stator 34, a gap is formed in which a so-called drive magnet 67 is arranged. This drive magnet 67 serves as a drive in a magnetic coupling and is annular in Fig. 1 and 2 and fixedly connected to the rotor bell 40. Preferably, the drive magnet 67 comprises plastic-bonded magnetic material, eg plastic material with embedded particles of hard ferrite, and is produced by plastic injection molding. Such a permanent magnet produced is also referred to as a plastic-bonded ferrite magnet and can also be used to form the rotor magnet 36. Here, the rotor magnet 36 can be fixed by the plastic injection on the rotor bell 40. Alternatively, as a rotor magnet 36 and a hard ferrite magnet ring be attached separately to the rotor bell 40, for example by gluing or pressing, or you could use individual magnets made of rare earth, such as neodymium.

In Fig. 1, the drive magnet 67 is separated by an annular partition 82 of a so-called driving magnet 92 which is "taken along" during operation of the magnetic coupling upon rotation of the drive magnet 67 and arranged in cross-section parallel to the drive magnet 67. This partition 82 is preferably liquid-tight but magnetically transparent, e.g. made of plastic. As shown, the upper end of the annular dividing wall 82 is liquid-tightly connected to the upper end of the bearing tube 30 via an annular ridge 80. Further, the lower end of the partition 82 is liquid-tightly connected to the lower end of the annular stator carrier 34 via an annular ridge 74. The annular webs 80 and 74 each extend perpendicular to the axis of rotation of the outer rotor 26. Thus, the bearing tube 30, the web 80, the partition 82, the web 74 and the stator 82 a meandering in cross-section part, which in the region of the driving magnet 92 as a gap pot is trained. This containment shell is integrally formed according to a preferred embodiment and e.g. made of plastic.

The containment shell passes over the outer periphery of the annular ridge 74 into a cylindrical portion 94 which, as shown, serves to secure a lid 88 to form a liquid-tight pump housing 86 therewith. The lid 88 may e.g. by means of a (not shown) screw fastening, a (not shown) sealing ring, or by laser welding to the cylindrical portion 94 are attached. On the cover 88, an inlet 96 is provided, via which a fluid can pass into the pump housing 86, which can emerge from the pump housing 86 via a schematically illustrated outlet 98.

In the interior of the pump housing 86, a delivery wheel 90 is provided to form the fluid pump 84. In Fig. 1, the feed wheel 90 is disposed on a pump shaft 106 which is formed in axial extension to the shaft 46 of the outer rotor 26. Both waves are liquid-tight separated from each other by the liquid-tight end 60 of the inner recess of the bearing tube 30.

The pump shaft 106 forms a fixed axis on which the feed wheel 90 is rotatably mounted in Fig. 1 in a circular bearing 108 relative to the axis. The rotary bearing 108 is preferably realized by so-called hybrid bearings. These hybrid bearings have ceramic balls and bearings made of a corrosion-resistant stainless steel alloy. They are manufactured eg by the company GRW and are especially for blood pumps and Dental drill used. With such bearings you get the desired lifetimes even in unusual fluids.

As an alternative to the fixed axis, it is possible to provide for the support wheel 90 a rotating shaft, which, like the shaft 46 of the outer rotor 26, is mounted in a bearing tube (not shown), which, like the bearing tube 30, is then formed integrally with the containment shell and protrudes from this down, so mirror image of the bearing tube 30th

The feed wheel 90 is preferably formed integrally with the driving magnet 92 which, by cooperation with the driving magnet 67, forms the magnetic coupling, i. when the drive magnet 67 rotates, the driving magnet 92 also rotates, thereby driving the delivery wheel 90, whereby it draws a fluid through the inlet 96 and pumped out again via the outlet 98, as indicated by arrows. As fluids, liquid media, e.g. Coolants, and / or gaseous media find application. Furthermore, instead of a centrifugal pump, any other turbomachine may be provided, e.g. a compressor for a refrigerant.

In Fig. 1, the magnetic coupling is formed by a coupling of the radial magnetic fields of the drive magnet 67 and the driving magnet 92. Therefore, this magnetic coupling is hereinafter referred to for clarity as a radial magnetic coupling.

Fig. 2 shows an exploded view of the arrangement of Fig. 1, in which the lid 88 of the pump housing 86 is not shown. From Fig. 2, in particular, the one-piece, meander in cross-section design of the bearing tube 30, the web 80, the partition 82, the web 74 and the stator 34 is clearly visible. Furthermore, the design of the inner stator 22 and the one-piece design of the feed wheel 90 with the driving magnet 92 are illustrated in FIG.

3 shows, in an enlarged, three-dimensional sectional view, a second embodiment of the arrangement for conveying fluids with the fluid pump 84 and the electronically commutated external-rotor motor 20, which differs slightly from FIG. This arrangement is exemplarily mounted in a recess 66 of a fan housing 68, in which the fan blades 64 of the electronically commutated external rotor motor 20 rotate during operation, cf. Fig. 4 and 5. The fan housing 68 has, for example, the usual square shape of a device fan and has in its corners each have a mounting hole 70th In contrast to FIG. 1, in FIG. 3 the rotor bell 40 is surrounded, as shown, by a plastic part 63, on which the fan blades 64 are formed by plastic injection molding in the manner shown. Further, the partition wall 82 is not disposed between the bearing tube 30 and the stator support 34, but at the lower ends thereof. Thus, the driving magnet 92 is not arranged in cross-section parallel to the drive magnet 67, but rather in axial extension to this.

As is particularly clear from Fig. 5, the partition wall 82 in the second embodiment forms an annular ridge between the lower end of the bearing tube 30 and the lower end of Statorträgers 34, which are liquid-tightly connected to each other by the partition wall 82 and in the region of the driving magnet 92 form a split pot. This containment shell is preferably integral and e.g. made of plastic, and passes over the outer periphery of the annular partition wall 82 in the cylindrical portion 94, which in turn serves to attach the lid 88. The cylindrical section 94 is shown in FIG. 3 by way of example in streamlined form as a streamlined channel.

By arranging the driving magnet 92 in axial extension to the drive magnet 67, the magnetic coupling is formed by a coupling of the axial magnetic fields of these permanent magnets. Therefore, this magnetic coupling is hereinafter referred to for clarity as axial magnetic coupling. In order to ensure a trouble-free functionality of this axial magnetic coupling, a permanent magnet with a strong axial magnetic field is preferably used for the entrainment magnet 92, e.g. a rare earth magnet.

Fig. 4 shows a longitudinal section through the arrangement of Fig. 3, in which the formation of the outer rotor 26 with the rotor bell 40 and the rotor magnet 36 is clearly visible.

5 shows an exploded view of the arrangement from FIG. 5, in which, in particular, the one-piece construction of the containment shell and the aerodynamic configuration of the cylindrical portion 94 can be seen.

operation

In operation, the external rotor motor 20 with the outer rotor 26 forms a fan whose fan blades 64 rotate in the fan housing 68. In FIGS. 1 to 5, this fan is shown by way of example as an axial fan, which upon rotation of the fan blades 64 in FIG known manner generates an axial flow of air. Alternatively, the fan can be designed, for example, as a diagonal fan or radial fan. The fan design used depends on the particular requirements.

Upon rotation of the outer rotor 26, the drive magnet 67 is also rotated, which is e.g. can be magnetized six- or eight-pole. The drive magnet 67 drives the driving magnet 92, which is also magnetized in this case six- or eight-pole, and takes this in the rotation with. If the drive magnet 67 rotates, e.g. counterclockwise, the magnetic coupling consequently also rotates the driving magnet 92 at the same speed in the counterclockwise direction. The arrangement shown in FIGS. 1 to 5 thus operates on the principle of a synchronous motor. Alternatively, operation with slippage is possible.

By the forced rotation of the driving magnet 92 and the feed wheel 90 is rotated so that it sucks a corresponding fluid through the inlet 96 and pumped through the outlet 98 back to the outside. Such an arrangement may e.g. be used to aspirate and pump out in a fountain, or to pump blood in a heart-lung machine, or to transport a cooling liquid in a closed cooling circuit, the feed wheel 90 then has the function of a circulation pump.

Since the lid 88 is liquid tightly connected to the cylindrical portion 94, e.g. by laser welding, it can not escape from the pump housing 86 when conveying a liquid to the outside. This contributes to that the section 94 is free of openings of any kind. This is possible because the electronically commutated external rotor motor 20 and the fluid pump 84 according to the invention can be mounted independently of each other and in a very simple and reliable manner, see. Figs. 2 and 5. For example. it is not necessary during the assembly of the electronically commutated external rotor motor 20 to have access to the end 60 of the inner recess of the bearing tube 30, or on that side of the split pot, on which the fluid pump 84 is formed. In particular, before assembly of the outer rotor 26, the entire remaining part of the arrangement can be completely assembled. Likewise, the delivery wheel 90 of the fluid pump 84 with its rotary bearing 108 can be mounted from below on the stationary pump shaft 106 before the cover 88 is fastened.

Due to the small spatial distance between the drive magnet 67 and the driving magnet 92 in FIGS. 1 to 5, a strong magnetic coupling is formed according to the invention and a good efficiency of the arrangement is achieved. especially at low and medium speeds. Furthermore, this small distance makes it possible to realize the driving magnet 92 by a permanent magnet with a small diameter. This is important because the driving magnet 92 rotates in the fluid and consequently with a small diameter of the driving magnet 92 low friction losses occur in this fluid. This contributes to the good efficiency of the arrangement. Furthermore, according to the invention a low overall height and a high degree of integration are achieved.

Naturally, many modifications and modifications are possible within the scope of the present invention.

Claims

claims

1. Arrangement for conveying fluids, comprising:

An electronically commutated external rotor motor (20) having a stator (22) arranged on a stator carrier (34) and a rotor (26) connected to a first permanent magnet (67) and rotatably mounted in a bearing tube (30) relative to the stator, which bearing tube is arranged at least partially radially within the stator carrier, wherein the first permanent magnet (67) in a space between the stator (34) and the bearing tube (30) is arranged; a fluid pump (84) having a rotatable within a pump housing (86) arranged conveying wheel (90) which is connected to a second permanent magnet (92), wherein between the first permanent magnet and the second permanent magnet, a liquid-tight but magnetically transparent partition (82) provided is and the first permanent magnet (67) by interaction with the second permanent magnet (92) forms a magnetic coupling for the fluid pump (84), which magnetic coupling upon rotation of the rotor (26) causes rotation of the delivery wheel (90) of the fluid pump (84).

2. Arrangement according to claim 1, wherein the first permanent magnet (67) between the bearing tube (30) and the partition wall (82) is arranged, and the second permanent magnet (92) between the partition wall and the stator (34) is arranged.

3. Arrangement according to one of the preceding claims, wherein the first permanent magnet (67) and the second permanent magnet (92) are annular.

4. Arrangement according to one of the preceding claims, wherein the first permanent magnet (67) plastic-bonded magnetic material or embedded in plastic permanent magnets.

5. Arrangement according to claim 4, wherein the first permanent magnet (67) is made by plastic injection molding.

6. Arrangement according to one of the preceding claims, wherein the bearing tube (30), the partition (82) and the stator (34) are made of magnetically transparent material.

7. Arrangement according to one of the preceding claims, wherein one end of the bearing tube (30) via an annular web (80) is liquid-tightly connected to one end of the partition wall (82).

8. Arrangement according to claim 7, wherein the pump housing (86) is liquid-tightly connected to the other end of the bearing tube (30) and the other end of the partition wall (82), and in the region of the second permanent magnet (92) is formed as a gap pot.

9. Arrangement according to claim 8, wherein the gap pot is made of a magnetically transparent material, in particular of a plastic.

10. Arrangement according to one of the preceding claims, wherein the bearing tube (30), the partition wall (82) and the stator (34) are made as a one-piece part, in particular as a meandering in cross-section part, in which one end of the bearing tube with a End of the partition is connected and the other end of the partition is connected to one end of the stator.

1 1. Arrangement according to claim 10, wherein the one-piece part is made of a magnetically transparent material.

12. Arrangement according to claim 10 or 1 1, wherein the pump housing (86) is liquid-tightly connected to the other end of the bearing tube (30) and the other end of the partition wall (82), and in the region of the second permanent magnet (92) as a gap pot is trained.

13. Arrangement according to claim 12, wherein one end of the stator carrier (34) is fixedly connected to the containment shell.

14. Arrangement according to one of the preceding claims, wherein the electronically commutated external rotor motor (20) has a rotor bell (40) within which a rotor magnet (36) and the first permanent magnet (67) are arranged.

15. Arrangement according to claim 14, wherein fan blades (64) are arranged on the rotor bell (40).

16. Arrangement according to claim 14 or 15, wherein the rotor magnet (36) comprises plastic-bonded magnetic material or the like.

17. Arrangement according to one of claims 14 to 16, wherein the rotor magnet (36) is multipolar and in particular achtpolig formed.

18. Arrangement according to one of the preceding claims, wherein the delivery wheel (90) of the fluid pump with a pump housing arranged in the fixed, stationary pump shaft (106) is connected, and rotates in operation about this pump shaft.

19. Arrangement according to claim 18, wherein the pump shaft (106) in axial extension to a with the rotor (26) connected to the shaft (46) which is rotatably mounted in the bearing tube (30), wherein the two shafts liquid-tight from each other are separated.