EP1778981B1 - Assembly for transporting fluid - Google Patents

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

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 cold 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.
Similar devices are for example WO 2004/031588 A1 or off US Pat. No. 6,600,649 B1 known.

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 of the height and an increase in the integrity of the unit external rotor motor, magnetic coupling and fluid pump.

A further preferred development of the arrangement according to the invention is the subject matter 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.

Fig. 1

einen Längsschnitt durch eine erste bevorzugte Ausführungsform einer Anordnung zur Förderung von Fluiden gemäß der Erfindung,

Fig. 2

eine Explosionsdarstellung der Anordnung gemäß Fig. 1,

Fig. 3

eine Schnittansicht einer raumbildlichen Darstellung von einer zweiten bevorzugten Ausführungsform einer Anordnung zur Förderung von Fluiden gemäß der Erfindung,

Fig. 4

einen Längsschnitt durch die Anordnung gemäß Fig. 3, und

Fig. 5

eine Explosionsdarstellung der Anordnung gemäß Fig. 3.

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:

Fig. 1

a longitudinal section through a first preferred embodiment of a device for conveying fluids according to the invention,

Fig. 2

an exploded view of the arrangement according to Fig. 1 .

Fig. 3

3 is a sectional view of a three-dimensional representation of a second preferred embodiment of a fluid delivery arrangement according to the invention;

Fig. 4

a longitudinal section through the arrangement according to Fig. 3 , and

Fig. 5

an exploded view of the arrangement according to 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.

Fig. 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 exemplified in Fig. 2 is shown, for example, a stator with salient poles or a claw-pole stator, and this is separated by a substantially cylindrical air gap 24 from a permanent-magnet outer rotor 26. 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 off Fig. 2 especially clear. Below the Innenstators 22 is located in Fig. 1 a printed 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, for example, 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 in Fig. 1 is exemplified as a deep-drawn, cup-shaped sheet metal part and eg off 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. An appropriate fan housing will be added below Fig. 3 explained.

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 eg when mounting in Fig. 1 be pressed together with the shaft 46 from above into a bearing tube 30. The ball bearings 48, 50 can be held in the bearing tube by suitable holding elements, such as 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, for example by a snap ring.

The assembly of the shaft 46 with the ball bearings 48, 50 in the bearing tube 30 is made Fig. 2 especially clear. Naturally, this assembly can be done in many ways and is therefore not limited to a specific type of mounting. It should be noted, however, that the mounting method described at Fig. 1 allows the shaft 46 of the outer rotor 26 together with the finished pre-assembled ball bearings 48, 50 mounted from above in the bearing tube 30, so that the in Fig. 1 shown below end 60 of the inner recess of the bearing tube 30 may be closed liquid-tight, see. For this 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 in Fig. 1 and 2 annular and firmly 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 a ring-shaped partition 82 from 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, for example 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 split pot is integrally formed according to a preferred embodiment and, for example 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 arranged 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 in Fig. 1 is rotatably mounted 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 a rotating shaft for the support of the delivery wheel 90 which, just like the shaft 46 of the outer rotor 26, is mounted in a bearing tube (not shown), which then, like the bearing tube 30, is 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 sucks a fluid through the inlet 96 and again pumped out through 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 Fig. 1 in which the cover 88 of the pump housing 86 is not shown. Out Fig. 2 In particular, the one-piece, in cross-section meandering design of the bearing tube 30, the web 80, the partition wall 82, the web 74 and the stator 34 is clearly visible. Furthermore, in Fig. 2 the construction of the inner stator 22 and the one-piece design of the feed wheel 90 with the driving magnet 92 illustrates.

Fig. 3 shows in enlarged spatial sectional view of a second embodiment of the arrangement for conveying fluids with the fluid pump 84 and the electronically commutated external rotor motor 20, which is slightly different from Fig. 1 different. 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 is in Fig. 3 the rotor bell 40 as shown surrounded 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.

How out Fig. 5 is particularly clear, the partition wall 82 forms in the second embodiment, an annular ridge between the lower end of the bearing tube 30 and the lower end of the stator 34, which are liquid-tightly interconnected by the partition wall 82 and 92 form a split pot in the region of the driving magnet. This containment shell is preferably made in one piece and made of plastic, for example, and merges via the outer periphery of the annular dividing wall 82 into the cylindrical section 94, which in turn serves to fasten the cover 88. The cylindrical portion 94 is in Fig. 3 exemplified in streamlined form as streamlined groove.

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 Fig. 3 in which the formation of the outer rotor 26 with the rotor bell 40 and the rotor magnet 36 is clearly visible.

Fig. 5 shows an exploded view of the arrangement Fig. 5 in which, in particular, the one-piece design of the containment shell and the aerodynamic design 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 the Fig. 1 to 5 This fan is exemplified as an axial fan, which upon rotation of the fan blades 64 in 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 and the drive magnet 67 is rotated, which can be magnetized, for example 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, for example, the drive magnet 67 rotates in the counterclockwise direction, the magnetic coupling consequently also rotates the driving magnet 92 at the same speed in the counterclockwise direction. The in the Fig. 1 to 5 The arrangement shown 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 water or to pump blood in a heart-lung machine, or to transport in a closed cooling circuit, a cooling liquid, 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, for example, by laser welding, can not escape from the pump housing 86 in the promotion of 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. Fig. 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 containment shell, 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 the Fig. 1 to 5 According to the invention, a strong magnetic coupling is formed 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, a low height and a high degree of integration are achieved according to the invention.

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

Claims (19)

1. Arrangement for delivering fluids, which comprises:

   An electronically commutated external rotor motor (20) with a rotor (26) and a stator (22);

   a stator carrier (34) on which the stator (22) is arranged; a bearing tube (30) in which the rotor (26) is mounted so as to be rotatable relative to the stator (22) and which is arranged at least partly radially inside the stator carrier (34) and separated from this by an annular interspace;

   a first permanent magnet (67) which is connected to the rotor (26) and projects into the annular interspace;

   a fluid pump (84) with a delivery impeller (90) which is arranged in a rotatable manner inside a pump casing (86) and is connected to a second permanent magnet (92);

   a liquid-tight, but magnetically transparent partition wall (82) which is arranged between the first permanent magnet (67) and the second permanent magnet (92);

   wherein the first permanent magnet (67), by interacting with the second permanent magnet (92), forms a magnetic coupling for the fluid pump (84) which, when the rotor (26) rotates, causes the delivery impeller (90) of the fluid pump (84) to rotate.
2. Arrangement according to Claim 1, in which the first permanent magnet (67) is arranged between the bearing tube (30) and the partition wall (82), and the second permanent magnet (92) is arranged between the partition wall and the stator carrier (34).
3. Arrangement according to any one of the preceding Claims, in which the first permanent magnet (67) and the second permanent magnet (92) are annular.
4. Arrangement according to any one of the preceding Claims, in which the first permanent magnet (67) comprises plastics-bonded magnetic material or permanent magnets embedded in plastics material.
5. Arrangement according to Claim 4, in which the first permanent magnet (67) is produced by plastics injection moulding.
6. Arrangement according to any one of the preceding Claims, in which the bearing tube (30), the partition wall (82) and the stator carrier (34) are made of magnetically transparent material.
7. Arrangement according to any one of the preceding Claims, in which one end of the bearing tube (30) is connected in a liquid-tight manner to one end of the partition wall (82) via an annular web (80).
8. Arrangement according to Claim 7, in which the pump casing (86) is connected in a liquid-tight manner to the other end of the bearing tube (30) and the other end of the partition wall (82), and is formed as a split can in the region of the second permanent magnet (92).
9. Arrangement according to Claim 8, in which the split can is made of a magnetically transparent material, in particular of a plastics material.
10. Arrangement according to any one of the preceding Claims, in which the bearing tube (30), the partition wall (82) and the stator carrier (34) are made as an integral part, in particular as a part with a meander-shaped cross section, in which one end of the bearing tube is connected to one end of the partition wall and the other end of the partition wall is connected to one end of the stator carrier.
11. Arrangement according to Claim 10, in which the integral part is made of a magnetically transparent material.
12. Arrangement according to Claim 10 or 11, in which the pump casing (86) is connected in a liquid-tight manner to the other end of the bearing tube (3) and the other end of the partition wall (82), and is formed as a split can in the region of the second permanent magnet (92).
13. Arrangement according to Claim 12, in which one end of the stator carrier (34) is firmly connected to the split can.
14. Arrangement according to any one of the preceding Claims, in which the electronically commutated external rotor motor (20) comprises a rotor bell (40) inside which a rotor magnet (36) and the first permanent magnet (67) are arranged.
15. Arrangement according to Claim 14, in which fan blades (64) are arranged on the rotor bell (40).
16. Arrangement according to Claim 14 or 15, in which the rotor magnet (36) comprises plastics-bonded magnetic material or similar.
17. Arrangement according to any one of Claims 14 to 16, in which the rotor magnet (36) is formed with multiple poles and in particular eight poles.
18. Arrangement according to any one of the preceding Claims, in which the delivery impeller (90) of the fluid pump is connected to a stationary pump shaft (106) arranged in the pump casing and rotates about this pump shaft during operation.
19. Arrangement according to Claim 18, in which the pump shaft (106) is arranged in an axial extension to a shaft (46) which is connected to the rotor (26) and is mounted in a rotatable manner in the bearing tube (30), wherein the two shafts are separated from one another in a liquid-tight manner.

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