EP2640977B1 - Magnetically driven pump arrangement having a micropump with forced flushing, and operating method - Google Patents

Description

The invention is concerned with a pump arrangement with a micropump which can be driven magnetically (claim 1). This micropump works to deliver a volume flow of a liquid delivery medium, which can be more or less viscous. The invention also relates to an associated working method of such a magnetically driven micropump, which method can claim the flow of the forced flow, since this occurs only when the micropump is in operation (claim: 18).

The forced flow refers to the flow of the more or less viscous conveying medium.

In the prior art, the storage of the mentioned micropumps is problematic. Micropumps are of a size that is hardly larger than a thumbnail. Dimensions below 20 mm, in particular below 10 mm (maximum dimension of the micropump) are specified and such pumping devices - called micropumps - must be stored appropriately.

Proposals have been made in the prior art, cf. WO 02/057631 A2 (HNP microsystems). Precision bearing components are manufactured there separately and inserted into a less precise carrier or holder. The invention there, cf. There page 2, the first four paragraphs, speaks of an imprecisely manufactured stator and of simple, precise sleeves that are mechanically precisely manufactured. The latter are used in the former and connected to it by joining (soldering, gluing, pressing). As a result, it can be achieved that the highest accuracy can be achieved with manageable costs and low vertical integration or manufacturing complexity. In those there Figures 2 , 5 an axial channel section, 22b there, is shown rather incidentally, which allows fluid to flow back from an intermediate chamber (there Figure 2 , between 10 and 24) to the suction side . The channel is provided in the wall 30i as an inwardly open stepped bore and connects the intermediate chamber with the suction side for the return of fluid into the microsystem, cf. there also paragraph [74]. The mini system or microsystem according to the WO mentioned also has a drive, cf. there Figure 2 and page 9, line 5 and page 10, third paragraph. The drive A there is far from the actual pump arrangement or the microsystem M, there in Figure 2 as well as page 11, first paragraph, removed, spaced apart by a seal 24 there, which is not a bearing, a coupling 23 which receives the shaft, 40 there, and couples it to the motor drive A on the other side. In this understanding, said WO discloses a drive. This also contains a motor, which can have a magnet inside, but which is not a "magnetically driven micropump", which is Claim 1 claimed according to the opening four lines. In any case, not shown by this driven microsystem of the prior art are three radial bearing pieces, as they are named in claim 1.

Another type of pump is from the WO 2008/046828 A1 to see. This document relates to a type of nested pump in which two pumps work in one another, the two pumps MP and CP, there page 12, second and fourth paragraph as Circulation Pump and Main Pump. For an explanation, we refer to FIG. 6 there, which forms the main pump on the left-hand side with an inlet 207 and a pressure side 208 (viewed from top to bottom). This is MP. It has a rotor 701, which is in the there Figure 3 can be seen. The second flat pump CP can also be seen there, cf. Page 13, third paragraph. This second pump generates the flushing flow and it is in the picture Figure 3 To see a small hole which has no reference number, but which allows a mechanical coupling with a pin, not shown or described, which is coupled to the rear (not visible) side of the rotor 701 of the main pump. Only then is a coupling of the two pumps disclosed there possible so that they can rotate synchronously with one another. The reference symbols CP and MP are not found in the figures, instead the reference symbols 8470 in FIG Figure 3 to CP and the reference number 150 in Figures 7 and 8 for the main pump MP. The main pump itself does not generate any forced flow, but uses the auxiliary pump for this, as its names make clear. The auxiliary pump mounted on the right back of the rotor 701 of the main pump MP in FIG. 6 generates a flushing flow which cools the radial bearings 8355 and 8354 there. For this purpose lubrication can also be assumed, there page 9, lines 28/29. The flushing flow is directed back via the channel structure of FIG. 6 and again reaches the inlet 207, where it is again available to the main pump. An analysis of the bearing structure of FIG. 6 there shows that it does not correspond to the claimed structure with the three radial bearing pieces (first feature) and that it is also not a micropump as claimed in claim 1.

It is a technical problem (object) of the invention to achieve a structure of a pump arrangement with the micropump that manages with a minimal number of components, which are as simple as possible in terms of production and can be assembled precisely in terms of assembly. As a result, it is inexpensive. In a special aspect of the task, the manufacturing effort is to be at least partially substituted by assembly effort, whereby the necessary tight tolerances are also achieved. These are a sinequa-non for microsystems and micropumps. In a further aspect of this task, the micropump in the bearing area is also to be flushed or lubricated, which is a notable problem at speeds above 5,000 rpm.

As a solution, a pump arrangement with a micropump that is magnetically driven is proposed (claim 1). It conveys a liquid delivery medium. The micropump is held in place by a bearing bracket called the base. The magnetic drive takes place from an external magnet to an internal magnet, and the latter transfers the torque transmitted to it to the micropump via the axial shaft. The bearing bracket has three bearing pieces that are connected to it by joining. These "radial bearing pieces" cause the rotary bearing (also: guidance) of the axial shaft and also of the micropump. The radial bearing pieces are positioned and fixed in the bearing bracket, with one of the three bearings accommodating the outer rotor of the micropump so that it can rotate. This bearing for the outer rotor is arranged eccentrically to the shaft. In contrast, the inner rotor, which is driven with the axial shaft, is arranged centrally to the axial shaft. The pump itself contains the inner rotor and the outer rotor, both of which are meshed with one another and rotate with one another, but at different speeds.

The outer rotor is received in the "eccentric bearing" and is held there by a cover on the front side. The at least two further bearing pieces are provided for the shaft. One of these bearings is closer to the inner magnet and the other of the bearings (each shaft bearing) is closer to the micropump. Both bearings are preferably as far apart as possible in order to give the axial shaft good stability and concentricity.

With the terms that one bearing is closer to the magnet and another bearing is closer to the micropump, a relative relationship is expressed. Of course, one of the bearings can be "close" to the inner magnet, or it can be surrounded by an annular magnet (then the radial bearing has a small radial dimension). That is certainly included in the concept of relation. The other bearing is closer to the micropump and this term also includes the fact that it is arranged close to or near the micropump, even directly on the micropump for end-face support and storage. What is claimed is not the term "close", but a relationship between the bearings with a view of the internal magnet and the pump.

A channel structure (or: channel guidance) is provided to enable flushing or lubrication. This ensures (during operation) a forced flow. The channel structure has several sections, at least two of which are to be highlighted. A first channel section is arranged in the cover. A second channel section is arranged in the bearing bracket. The channel guidance in the sense of the channel structure thus enables the fluid conveying medium on the pressure side to be diverted via the cover and the bearing bracket to enable flushing and / or lubrication of all three named bearings.

The micropump is driven by an external magnet, which transmits a torque to the internal magnet, which is axially spaced from the micropump. This can be viewed as a "magnetic clutch" or as a magnetic torque transmission (claim 2) in the sense of the "magnetic drive" (claim 1).

The pump is held in the eccentric bearing by a cover on the face. The channel structure provides the forced flow in order to actively flush and / or lubricate the bearings with the pumped medium (the conveyed volume flow).

The two bearings for the shaft are clearly separated. A bearing is close by, especially even within the inner magnet, and is part of the bearing bracket. The other bearing is near or directly to the micropump and part of the bearing bracket.

The function-determining tolerances are (claim 1) combined on three precision bearings. Important dimensions are produced by precisely assembling these precision bearings to one another. After positioning, the precision bearings are connected to the bearing carrier by a joining process (a joining technique, claims 7, 10). For example, adhesive bonding, welding or soldering are used in order to meet the high demands on the tolerance in terms of assembly technology. The manufacturing costs of the individual parts can be reduced.

With the structure mentioned, the number of necessary axial bearings can also be reduced. The cover that holds the micropump in the eccentric bearing at the front is such a thrust bearing. Ceramic is preferably used here as a material in order to minimize wear. No axial bearing is required on the shaft side at the end of the shaft remote from the rotor (remote from the pump). The forces acting on the shaft are adjusted in such a way that such storage is unnecessary.

The following forces can be considered that can act on the shaft. An axial force component of the pump's inner rotor. Due to the sliding fit (polygon), no axial forces are transmitted to the shaft when the pump rotates. The magnetic drive (i.e. the torque transmission from the external magnet to the internal magnet, which is rotatably coupled to the shaft via a bearing bracket) could create an axial force component. However, if the axial positions of the inner magnet and outer magnet are coordinated in such a way that no axial force component arises, there is also no need to absorb such a force component from an axial bearing. Support for the lack of such a further axial bearing is the resulting pressure gradient of the pumped medium within the housing arrangement, which comes from the bearing bracket, a hood-shaped cap part placed thereon and an opposite cover is formed (claim 18).

The result is a hermetic seal and a pressure that builds up inside the housing, which is created by the work of the pump and the existing duct sections for the forced flow. At the end of the shaft remote from the pump, this is the drive or magnet-side end of the shaft, a pressure build-up will create a pressure gradient to the rotor-side end of the shaft, whereby the shaft is pressed during operation by the pressure gradient that builds up towards the pump. There is an axial bearing through the cover for the pump and for the end of the shaft on the pump side. Another axial bearing at the other end of the shaft can be omitted.

It should be mentioned that the shaft must naturally be rotationally rigid or rotationally rigidly coupled to the inner magnet, which is done via a magnet carrier (claim 6). Magnet carrier and inner magnet are constructed concentrically and the one bearing remote from the pump is preferably provided in the center of the inner magnet. The outer magnet is preferably concentric to the inner magnet, outside the dome-shaped cap, which is also called a containment can.

Components that are susceptible to failure can preferably be dispensed with due to the structure (claim 18). These are dynamic seals or shaft seals. The fact that the pump is hermetically sealed by the cover on the one hand and is seated in the bearing bracket, on the other hand, the bearing bracket has a hood-shaped cap as a containment shell opposite the cover and concentric to the shaft, which is also connected to the bearing bracket via static seals, the hood area can accommodate the internal magnet and are completely traversed by the fluid conveying medium that emerges on the pressure side of the rotating pump via said channel sections. In this way, the hood (hood-shaped cap) can also be cooled from the inside.

Due to the hermetic structure with exclusively static seals (containment shell to the bearing bracket and cover to the bearing bracket), the micropump can also convey dangerous media, crystallizing media or highly volatile media.

Long-term applications are also possible if the aforementioned dynamic seals, which are susceptible to wear, are omitted. The consequence of this is the active flow of the pumped medium through the containment shell (the hood-shaped housing part), but with further advantages. The dead volume is minimized and the medium to be conveyed (or better: the medium being conveyed) simultaneously serves to cool the containment shell, the bearing surfaces and the magnets, as well as lubricating the bearing surfaces.

The previously described force effect due to pressure difference (pressure gradient) is another resulting advantage. Due to the pressure difference between the area of the containment can (or better: the area of the inner magnet) and the rotor-side shaft end, a flushing flow can arise along the shaft, which flows through the bearing components of the shaft.

The shaft is still mounted in the bearing components, but rotates in a cavity between the bearing components through which the axial flushing flow runs.

By using a static drive with a stator that generates a rotating magnetic field without having rotating components, a minimal installation space is achieved. In such an application, the containment shell can be omitted and an external housing is used. An electrical connection, which supplies the stator with power for the formation of the rotating magnetic field and for transmission to the internal magnet, which is coupled to the shaft via the magnet carrier, can be hermetically sealed through an opening.

The inner magnet and the outer magnet then both become inner magnets, which are located within the surrounding housing. They differ as a stator and rotor. The external magnet creates a rotating magnetic field and remains static. The inner magnet rotates the shaft and lies inside the outer magnet.

With this type of drive, a minimal installation space is achieved, but if the hood-shaped housing part (the containment can) is omitted, the drive winding of the external magnet should be coated in order to be resistant to the conveyed media and to enable long-term use.

The hood-shaped housing part (also: cap) does not have to be omitted even when the stator is stationary (with a rotating magnetic field), but can also be present. Due to the material used (mostly metallic), eddy currents in this containment can cannot be avoided, which lead to heat generation. Such a heat development is counteracted by the internal cooling on a very large inner surface of the containment shell. In a preferred embodiment, over 50%, usually significantly more, of the inner surface of the cap can be cooled (claim 28). A remnant piece is used to connect the cap with the bearing bracket in a centering manner.

In one option, the first solution is designed in such a way that the bearing bracket is produced from metal or plastic by injection molding (claim 8). Nevertheless, the Radial bearing pieces are still manufactured separately and designed as precision bearing parts (claim 10). They are subsequently placed in the injection-molded bearing bracket and positioned and specified, for which purpose a joining technique can be used to reliably and accurately arrange the radial bearing pieces in the bearing bracket.

Also an option and preferred design in the first solution is the presence of a heating element which, however, is to be arranged in an injection-molded bearing bracket (claim 9). With it, a warming of the still little liquid or hardly liquid pumping medium is achieved in order to improve the cold start capability of the micropump.

Reference is made to claim 14 for a description of the conceptual content of the micropump. This is included here in support of the invention (claim 1). With regard to the cooling capacity of the dome-shaped cap, a large inner surface is to be understood to mean that it can amount to at least 50% of a total inner surface of the cap. Preferably, however, more than 70% of the entire inner surface of the cap can be cooled. In the embodiment with a stationary stator that generates a rotating field, the hood-shaped cap can be omitted and another, hermetically sealed housing can be placed on the bearing bracket. Since no mechanical rotations have to be coupled into the housing formed in this way, but power is only supplied via electrical lines, the inner rotor and outer rotor are located together in a housing formed of this type.

The compact structure creates short tolerance chains and short traction paths. The precise bearing pieces (claim 1) meet the requirements for low tolerances for the reliable function of the micropump and use in long-term applications.

With the claimed pumps (claim 5) practically (or almost) all types of fluid conveying media can be conveyed: particularly dangerous media, crystallizing media, e.g. urea, or volatile media, e.g. methanol, and if a heating element is preferred, also such Media that cannot be conveyed when cold, for example urea, water or methanol (as in automobiles).

The torque transmission from the external magnet and internal magnet (claim 2) can preferably be designed as a central rotary coupling (claims 3, 11).

The generated magnetic field of the external magnet can be generated by a stator (claim 4). The hood-shaped housing part can be omitted here.

An internal annular gear pump can be used as the micropump (claim 5), cf. WO 97/12147 A . The shaft is torsionally rigidly connected to the inner rotor and also rotationally rigid to the magnet carrier and the inner magnet sitting on it. Alternatively, an internal gear pump with involute teeth is used.

The inner magnet can be in one piece or in several pieces (claim 13). It is arranged on a carrier (claim 6). Preferred materials for the inner magnet are hard ferrite or higher-quality magnetic materials. In the case of a multi-part internal magnet, several individual magnets arranged in a ring can be attached to one another. If only an inner magnet is used, a ring magnet can preferably be used. Also "platelet-shaped" magnets (as magnetic pieces) made of higher quality magnetic material, e.g. NdFeB (as an example of a rare earth magnet) or SmCo (samarium cobalt) can be put together as segments to form a ring-shaped inner magnet.

Examples of such segments are the ring segments mentioned, which together (placed next to one another) result in the ring magnet as an internal magnet. In the example, a thickness of 2mm (thickness, measured radially) and a height of up to 10mm (measured axially) are possible.

Encapsulation or coating of this magnet (one or more parts) is recommended for the promotion of aggressive media (claim 13).

The channel structure, which - branched off from the pressure side of the micropump (claim 1) - provides the forced flow, has at least three channel sections. One is in the cover (preferably with a radial directional component) and another is in the bearing bracket (preferably with an axial direction). Yet another axial channel section is provided, which runs in the cover and forms the outlet on the pressure side. Another channel section can be located in the bearing bracket (claim 15), which also runs axially but is traversed by the conveying media in the opposite direction (claim 16). At the point of change in flow direction, i.e. between the two axial channel sections, there is a flat, preferably ring-shaped receiving space which is formed axially between a lower end of the inner magnet and an upper surface of the bearing bracket (claim 17). Fed from the pressure side of the micropump, the housing fills practically completely from this channel section with the pressure level of the output side of the micropump. The containment shell serves as the boundary wall.

The additional axial channel section in the bearing bracket guides the pumped medium to the outlet.

Corresponding to the dome-shaped design of the containment shell, the bearing carrier can have a concentrically formed elevation or extension around the axis, which preferably carries the first bearing at its end, opposite which the magnet carrier is and is fixedly fixed to the shaft. A reduced radial dimension of the elevation or extension can form a circumferential annular space in which a significantly longer inner magnet can be inserted axially, the axial length of which is longer than that of the magnet carrier.

By using the increase or extension, the distance between the two bearing pieces that form the shaft bearing can be selected as large as possible.

Regarding the course of the forced flow of the conveying medium, it can be noted that the opening on the suction side is located in the housing cover, as is the outlet on the pressure side. Only the inlet is in alignment with the micropump. The outlet is offset radially with respect to the micropump. The axial channel sections in the bearing carrier are preferably also arranged circumferentially offset from one another.

Through such a fluid guide, all areas of the pump can be actively flowed through and the dead volume of the pump is limited. The pressure difference that develops in the containment can compared to the micropump in the suction area ensures an axial flushing flow along the shaft. This "forced flushing" also ensures lubrication of the shaft bearings and the eccentric pump bearing and, if a containment shell is present, it cools it.

Figur 1

ist ein vertikaler Schnitt durch ein erstes Beispiel einer magnetisch antreibbaren Pumpenanordnung mit Mikropumpe. Der Lagerträger 22 ist Zentrum des Aufbaus, oberhalb ist ein haubenförmiger Gehäuseabschnitt 24 und unten ein Deckel 26, der axial-lagernd an der Mikropumpe P mit dem Außenrotor 80 anliegt. Der haubenförmige Gehäuseabschnitt, der im Folgenden auch Spalttopf genannt wird, ist Teil eines Gehäuses 20, welches Spalttopf 24, Lagerträger 22 und Deckel 26 umfasst.

Figur 2

ist eine Ansicht von der Deckelseite (in Figur 1 von unten), wobei die Richtungen oben, unten lediglich auf die Darstellung in den Figuren Bezug nehmen und den Aufbau als solches nicht hinsichtlich seiner Einbaurichtung präjudizieren. In Figur 2 ist eine Schnittebene III-III eingezeichnet, die in Figur 3 dargestellt ist, wobei die Schnittführung drei Knicklinien A, B und C aufweist, die bei der Betrachtung der Figur 3 zu berücksichtigen sind. Dadurch wird die Kanalführung 23, die im Folgenden näher erläutert wird, in Figur 3 deutlicher, als sie in Figur 1 gezeigt werden kann, welche einem Schnitt III'-III' entspricht, der keine Knickstellen hat, sondern mittig eben verläuft.

Figur 2a

ist eine Ausschnitts-Vergrößerung des Zentrums der Figur 2, um die zur Figur 2 gemachten Aussagen zu verdeutlichen. Besonders tritt hier die Mikropumpe P hervor, die einen Außenrotor 80 und einen Innenrotor 82 aufweist. Die Welle 10 als Axialbezug der Anordnung greift formschlüssig mit einem Mehrkant-Abschnitt 10a in eine entsprechend geformte Innenöffnung des Innenrotors 82, um diesen anzutreiben.

Figur 3

ist die Schnittansicht mit der Schnittführung III-III aus Figur 2 und den zu berücksichtigenden Knicklinien A, B und C, wie dort dargestellt. Zusätzlich ist in Figur 3 eine Fluidführung F von der Saugseite zur Druckseite der Mikropumpe ebenso eingezeichnet, wie eine Spülströmung F'. Die zugehörige Kanalstruktur 23 wird oft synonym für die Strömungsführung des liquiden Fördermediums verwendet, das der Kanalstruktur 23 folgt. Die Kanalstruktur 23 besteht aus mehreren zu erläuternden Abschnitten.

Figur 4

ist ein weiteres Ausführungsbeispiel, wie die Anordnung nach Figuren 1 und 2 in ein Gehäuse 20* eingesetzt ist und von einem Antriebsmotor 95 über einen drehbaren Außenmagneten 44 angetrieben wird. Als Referenz dienen die Welle 10 und der haubenförmige Abschnitt 24 des hier innen liegenden Gehäuses 20.

Figur 5

ist ein weiteres Ausführungsbeispiel mit einem stehenden Statormagneten 48, der ein magnetisches Drehfeld zu erzeugen vermag und den Innenmagneten 40 bei Übertragung eines Drehmoments antreibt. Durch die elektrische Erzeugung des Drehfeldes ist der Zugang zu dem modifizierten Gehäuse 20' über einen Anschlussstecker 91 erreicht, der von außen keine drehbare Welle in das Gehäuse 20' überführen muss. Zusätzlich ist eine integrierte Heizung 71,72 dargestellt, die eine besondere Ausführungsart ist.

Embodiment examples of the invention are explained in the following figures. The understanding of the invention (s) is deepened and supplemented with them.

Figure 1

is a vertical section through a first example of a magnetically drivable pump arrangement with a micropump. The bearing support 22 is the center of the structure, above is a hood-shaped housing section 24 and below is a cover 26, which rests axially on the micropump P with the outer rotor 80. The hood-shaped housing section, which is also called the containment can in the following, is part of a housing 20 which comprises the containment can 24, bearing support 22 and cover 26.

Figure 2

is a view from the lid side (in Figure 1 from below), whereby the directions above and below merely refer to the representation in the figures and do not prejudice the structure as such with regard to its installation direction. In Figure 2 a section plane III-III is shown, which in Figure 3 is shown, the section having three crease lines A, B and C, which when viewing the Figure 3 are to be considered. As a result, the channel guide 23, which is explained in more detail below, is shown in FIG Figure 3 clearer than it is in Figure 1 can be shown, which corresponds to a section III'-III ', which has no kinks, but runs flat in the middle.

Figure 2a

is an enlarged section of the center of the Figure 2 to the for Figure 2 to clarify the statements made. The micropump P, which has an outer rotor 80 and an inner rotor 82, stands out in particular. The shaft 10 as the axial reference of the arrangement engages positively with a polygonal section 10a in a correspondingly shaped inner opening of the inner rotor 82 in order to drive the latter.

Figure 3

FIG. 3 is the sectional view with the section III-III from FIG Figure 2 and the kink lines A, B and C to be considered, as shown there. In addition, in Figure 3 a fluid guide F from the suction side to the pressure side of the micropump is also shown, as is a flushing flow F '. The associated channel structure 23 is often used synonymously for the flow guidance of the liquid conveying medium that follows the channel structure 23. The channel structure 23 consists of several sections to be explained.

Figure 4

is a further embodiment, like the arrangement according to Figures 1 and 2 is inserted into a housing 20 * and from a drive motor 95 via a rotatable external magnet 44 is driven. The shaft 10 and the hood-shaped section 24 of the housing 20 located on the inside serve as a reference.

Figure 5

is a further embodiment with a stationary stator magnet 48, which is able to generate a rotating magnetic field and drives the inner magnet 40 when a torque is transmitted. The electrical generation of the rotating field provides access to the modified housing 20 'via a connector 91, which does not have to transfer a rotatable shaft from the outside into the housing 20'. In addition, an integrated heater 71, 72 is shown, which is a special embodiment.

To be conveyed is a physically not shown liquid conveying medium, which can have different material compositions, but is suitable for conveying with a micropump. For the automotive industry, this is, for example, urea, water or methanol. Hazardous media, for example in chemistry, crystallizing media, for example the urea mentioned in automobile construction, or highly volatile media, for example methanol in fuel cell technology, can equally be conveyed with the exemplary embodiments described below.

The promotion is a continuous promotion while the micropump P is running, which is used in a bearing 3, the rotor mount in Figure 1 is called.

Figure 1 shows a shaft 10 as a central component, which is arranged in the axis of the structure. It is rotatably mounted in two further bearings 1 and 2, the two bearings being at a distance 'a' from one another.

All three named bearings 1, 2 and 3 are designed as bearing pieces that are precision bearing parts. They are inserted separately in the bearing bracket 22 and fixed there by means of a joining technique after positioning. Gluing, soldering or welding are suitable as a joining technique.

Oxide ceramics, non-oxide ceramics, metal or even plastic come into consideration as the material for the precision bearings, which are specially manufactured for precision. Examples of oxide ceramics are aluminum oxide or zirconium oxide. In a special embodiment, when high wear is to be expected or when a long service life is desired, ceramics are used. In normal, low-wear applications, however, metal can be used. Plastic is also possible for the bearings, which is preferred for a one-piece design of the bearing bracket 22 by injection molding directly with the production of the bearing bracket 22 as plastic storage areas, but are not separate bearing pieces, but just storage areas, or - from a functional point of view - "bearings".

The structure of the housing 20 in Figure 1 initially comprises the three components: hood-shaped cap 24, bearing carrier 22 and cover 26. The bearing carrier is designed so that it accommodates the three named radial bearings 1, 2 and 3 and represents the core of the magnetically driven micropump or the associated housing structure. The bearing bracket can be relatively roughly tolerated and made of less rigid materials, such as aluminum or plastic. The precision and accuracy to be obtained is achieved by installing the bearing pieces, which are connected to the bearing bracket 22 by joining.

The bearing bracket 22 also serves to accommodate all static seals that are not specifically named in the figures but are immediately apparent to the person skilled in the art. These are O-rings and seals for fastening the cover 26, the hood-shaped cap 24 (also called containment can) and the magnetic drive unit, which are shown in, for example Figure 4 with its lower portion and a rotatable external magnet 44 can be seen.

The assembly of the cover 26 from the underside of the bearing bracket 22 is shown in FIG Figure 1 shown symbolically with an engaging screw device 22 '. This assembly can, however, also be carried out as shown for assembly of the hood-shaped cap 24 on the other side of the bearing bracket 22, namely by means of hold-down devices 21, via which an assembly force of a further screw device 22 ″ is uniformly transmitted to the circumference of the lower assembly flange of the hood 24 If the cover 26 is made of ceramic, for example, such an arrangement with a hold-down device is recommended, which is shown in FIG Figure 1 is not shown separately.

The magnetic drive system is placed inside the dome-shaped cap 24 around the shaft 10 at its upper end. The shaft here has an end “remote from the pump” or “remote from the rotor”, which is also called the “drive or magnet-side” end of the shaft 10. The other end 10a of the shaft 10 engages positively in the inner rotor 82, as at Figure 2a can be seen. Here is the end of the shaft 10 on the pump side, which is axially supported against the cover 26.

It is driven from the outside (in Figure 1 not shown) and acts as a coupling of a torque, in particular as a central rotary coupling, with the inner magnet 40 and one in the Figures 4 and 5 External magnet 44 or 48 shown concentric to one another are arranged. A central rotary coupling is used when the outer magnet and the inner magnet rotate together. They are then arranged concentrically to one another.

The inner magnet 40 is axially longer than a carrier 42 for this inner magnet, which is non-rotatably connected to the shaft 10 and which is also non-rotatably connected to the internal magnet 40. This inner magnet carrier is designed to be axially shorter and lies at the upper end, but not in a touching manner, but leaving a gap near the upper wall 24b of the dome-shaped cap 24.

Mention should be made of an achievable “relatively large” distance between the two first bearings 1 and 2, which are provided for the rotary bearing of the shaft 10. The lower bearing is close to the micropump P, actually directly on the micropump P, and serves as an opposing axial bearing for the two rotors 80, 82. The axial bearing opposite these rotors is the cover 26 with its inner region. An achievable distance 'a' is more than three times greater than the axial height of one of the two shaft bearings 1, 2.

The bearing 2 remote from the pump is positioned on an elevation or extension 22a arranged concentrically to the hood-shaped cap. At its (upper) end, it carries the named bearing piece 2 and leaves an annular gap opposite the inner magnet carrier 42. The elevation or extension is also geometrically designed so that it forms a cylindrical annular gap opposite the inner magnet 40. The inner magnet 40 in turn has an axial distance to leave an annular space 23d, which forms a section of a channel structure 23, which will be described later.

Since the inner magnet 40 also leaves a cylindrical annular gap to the inner surface of the dome-shaped cap 24 (containment shell), a fluid can flow through the entire interior of this dome-shaped cap, provided that no geometric parts, which are described above, are located there. In particular, an inner wall of the hood-shaped cap 24 should be mentioned, which can be cooled by a fluid flow to be described, for which purpose the said cylindrical annular gap is provided outside the inner magnet 40.

The shaft 10 has an annular space 22b between the two bearing pieces 1, 2, which is dimensioned radially larger than a diameter of the shaft 10.

The shaft 10 is arranged centrally with respect to the hood-shaped cap 24, while the rotor receptacle as a bearing piece 3 is eccentric. This bearing piece 3 accommodates the outer rotor 80 in an eccentric manner relative to the centrally rotated inner rotor 82. Figures 2.2a show the pump P with inner rotor and outer rotor 80, 82 and also the widening and tapering of the rotating pumping chambers, which is characteristic of a gerotor pump. Alternatively, instead of the gerotor pump according to Figure 2a an internal gear pump can also be used, which is not shown separately in the figures.

The fluid is supplied (on the suction side) via a channel section 23a (suction side). The outlet of the pump P opens into an in Figure 2a apparent pressure kidney, which merges into a radial channel section 23b. Said sections 23a, 23b are sections of the channel structure 23 which guide the fluid from the inlet F _u (suction side) to the outlet F _D (pressure side).

The pressure side F _D 'is located at the outlet of the pump P in the radial channel section 23b. Between F _D 'and F _{D there} is a further section of the channel guide 23 which extends through the bearing bracket 22 and - in the example - has two axial channel sections 23c and 23e. These two channel sections are in Figure 2a clearly visible. They are circumferentially offset from one another, but both extend in the axial direction in the bearing bracket 22.

The axial section of the Figure 3 is based on the Figure 2 to explain. The section plane III-III has three kinks or lines A, B and C. A lies in the center of the axis, respectively the shaft 10. The second kink line B lies in the center of the first axial section 23c of the fluid guide (the channel structure 23). The second kink line lies in the second axial section 23e of the channel structure 23.

Further axial sections of the channel structure 23 can be seen in the cover 26. On the inlet side (suction side) of the fluid F, the section 23a is provided. On the print side the arrangement of the Figure 3 an additional axial section 23f is provided in the cover 26.

Another radial section of the channel guide 23 is the transfer of the direct pressure outlet of the pump P along the section 23b of the channel structure 23 to the first axial section 23c in the bearing bracket 22.

With the channel structure 23, a forced flow is generated which occurs when the pump P is in operation and not only ensures useful delivery of the fluid F, but also performs several tasks.

The bearings 1, 2 and 3 described are lubricated or flushed. Also both. The can 24 (as a hood-shaped cap of the housing 20) is cooled from the inside, the cooling surface being at least 50% of the total inner surface of the hood 24, but preferably being above 70%.

This can be seen from a first elevation 22c of the bearing bracket 22, which merges in a tapering manner into the elevation or extension 22a, which was previously described. The hood 24 rests on the edge-side surface in a touching manner to a certain extent and is fastened with the circumferential hold-down device 21 and correspondingly positioned screws, of which in Figure 1 a screw 22 ″ can be seen, attached to the bearing bracket 22. Preferably, three such mounting screws can be provided (not shown). Circumferential static seals that are not separately numbered but can be recognized by the hatching can be seen in all figures.

With the axial channel section 23c, the fluid F on the pressure side is supplied as pressurized fluid F _D 'not immediately to the outlet in the cover 26, but first to the aforementioned annular space 23d, which is located between an upper surface of the bearing bracket (between the shoulders 22c and 22a, and a downward-facing surface is formed of the internal magnet 40. This section 23d is flat and belongs to the channel structure 23.

The axial section 23c feeds pressurized fluid to this flat annular space 23d, which fluid is distributed into the remaining free spaces within the “hood” 24 and flows through there. It can flow off again via the second axial channel section 23e and can be fed via the axial channel section 23f in the cover 26 to the outlet side or pressure side of the micropump arrangement with bearing according to the figures.

A large part of the inner surface of the cylindrical wall 24a of the dome-shaped cap 24 can thus be cooled.

Is in Figure 1 due to the position of the cut, only the axial channel section 23e of the channel structure 23 in the bearing bracket (on the pressure side) can be seen and if no really radially reaching channel segment 23b can be seen in the cover 26, if the cutting line is changed, Figure 2a the radial section 23b and the first axial section 23c can be seen.

In addition to the main flow of the fluid F, a flushing flow F 'should also be mentioned. It penetrates through the bearing surfaces of the precision bearings along path F 'from Figure 3 . It flushes both bearings 1, 2 and, due to the pressure difference, reaches pump P on its suction side. Lubrication of the bearings is also achieved.

The flushing flow F 'leads along the shaft and into the central cavity 22b, through which the shaft 10 reaches or in which it rotates while it is rotatably mounted by the two bearing pieces 1, 2 spaced apart by' a '.

The path along the fluid guide 23 should again be clearly summarized and shown.

The liquid delivery medium is sucked in on the suction side through the housing cover 26 and fed to the axial channel section 23a in the micropump P with rotors 82, 80, or sucked in by the latter. It follows the rotating conveyor chambers according to Figure 2a the micropump (also called "pump" for short) and is fed to the pressure-side section of the fluid guide. The outlet of the pump P on the pressure side ends in the radial channel section 23b. At its end, it is fed to the internal channel 23c in the bearing bracket 22 and passed into the containment can 24. The fluid flows through this containment shell (the hood-shaped cap 24) and reaches the pressure-side opening in the housing cover 26 via a further axial channel section 23e.

In the cover 26 an aligned channel section 23f is provided, which is the continuation of the axial channel section (or channel segment) 23e. This fluid flow actively flows through all areas of the pump. The dead volume of the pump, however, is limited. The pressure difference between the shaft end on the rotor side and the shaft end of the shaft 10 on the drive side ensures a forced flushing F 'and the associated lubrication of the bearings 1, 2 by the liquid delivery medium.

The described bypass flow, which is called the flushing flow F ', follows the pressure gradient between a delivery pressure in the containment can area (inside the hood 24) and the low pressure in the area of the rotor bearing (the suction side). The medium flowing through the containment shell 24 simultaneously serves to cool the containment shell and the internal magnet 40.

Due to the rotating magnetic field and the mostly metallic construction of the hood-shaped cap 24, heat is generated via eddy currents, the dissipation of which is used by the fluid flow.

In another embodiment that consists of Figure 5 results, the containment shell can also be omitted. In Figure 5 the hood-shaped cap is still shown, but is unnecessary due to the drive shown there and could be omitted. This embodiment, not shown, is made possible by the fact that an outer housing 20 ′ is formed which is created outside the outer magnet 48 and is connected to the bearing carrier in a sealing manner. This can be done by a screwing device, of which two Screws 22 '"are visible. The hold-down device 21 and the hood-shaped cap 24 are omitted.

Both the external magnet 48, which carries current-carrying windings 49 (which is not shown), as well as the internal magnet 40 are then arranged in the same space and characterized by their designation as external and internal. Due to the lack of rotational movement of the external magnet 48, the torque is transmitted to the internal magnet 40 via the rotating field.

The electrical energy is supplied via the connection plug 91, which represents an opening in the motor housing 28, which is part of the modified housing structure 20 '. An integrated control 90 on a circuit board is shown and generates the current flows in the spatially distributed windings 49 for generating the rotating field.

In a special embodiment, which is not binding only for this example, but can also be used for the other examples, a heating winding 72 is arranged around the shaft in the bearing bracket 22. Another heating coil 71 can be located closer to the cover 26 and surround the pump P.

The heating windings 71, 22 are electrically conductive resistance windings to which current is applied. This can also be supplied via the connection cover 91.

In other areas of the Figure 5 this example of execution corresponds to that of Figures 1 and 2 .

The integrated heaters 71 and / or 72, which can be present individually or in combination, improve the cold start capability of the pump when thick or viscous pumping media are to be conveyed that cannot yet be conveyed due to the reduced ambient temperature, for example in automotive engineering.

The heater can particularly advantageously be used in connection with a bearing bracket 22 which is produced by injection molding, for example from metal or plastic.

Figure 4 shows another embodiment, which the structure of the Figures 1 / 3 used. Here a motor 95 can be seen as a drive on a higher-level housing structure 20 *, which engages mechanically with a motor shaft 94 in a cover plate 29 of this housing structure 20 * and allows a rotating external magnet 44 to rotate via a radially expanding external magnet carrier 45. This takes, coupled via a magnetic field and through the hood-shaped cap 24, the Inner magnet 40 rotates with it and forms a central rotary coupling. The motor 95 is controlled by an electrical controller 96 which is shown in FIG Figure 2 can be seen in the section and is preferably placed at the upper end of the motor 95.

Inner magnet 40 and outer magnet 44 are advantageously concentric with one another and not offset from one another in the axial direction. This minimizes axial forces that can (t) act on the shaft 10 through the magnetic field.

The higher-level housing structure 20 * is connected to the bearing bracket 22 in a mechanically sealing manner. This can be done again by a screwing device, of which two screws 22 '″ are visible, as also in FIG Figure 5 shown.

Remarkable, also in this embodiment, is the use of only one axial bearing of the shaft 10, namely on the cover 26 and the free shaft end near the upper horizontal wall 24b of the hood-shaped cap 24. Also noteworthy, not only in this embodiment, but also in the others Embodiments, the use of no dynamic seal, so no shaft seal to be provided, which has to seal against a rotating part.

The underside of the cover 26 is 26d and the inlet and outlet are provided on it, which are provided here with O-ring seals and have a diameter that is larger than the diameter of the outgoing channel sections.

The lower surface of the bearing bracket 22 is 22d. The cover 26 is placed on it in order to achieve the axial guidance of the channel sections 23e and 23b as well as to lead the axial section 23a to the suction side of the pump P and also to lead the radial channel section 23b to the discharge side of the pump P on the pressure side.

The following is to be said of the drive-side magnet constructions made up of external magnet 44 and internal magnet 40, which also applies to the examples of Figure 1 to 3 Claimed validity.

At the drive-side end of the shaft 10, the inner magnet 40 arranged there over the magnet carrier 42 is preferably in one piece (made from one piece). It can consist of hard ferrite. Another construction is the use of the encapsulation of a plastic-bonded magnetic material around the shaft end (in the area of the outer magnet 44) and without a magnet carrier on the shaft side. As a further alternative, the inner magnet 40 can be made from several parts. These several parts are held on the magnet carrier 42. For this purpose, several individual magnets (arranged in a ring) (as segments or sectors) can be used, which are assembled on the magnet carrier 42. Is only a piece of a magnet is provided, it sits as a ring magnet on the magnet carrier 42 and is joined to it in a rotationally fixed manner.

The assembly of the several individual magnet pieces (in the form of “plate-like” magnets), which are made of high-quality magnetic material, can take place on the magnet carrier 42. Rare earth magnets are examples of such plate-shaped magnets.

If aggressive media are to be conveyed, the individual magnets (as magnetic pieces) can also be coated or encapsulated. Such magnets would only turn out to be coated or encapsulated if they came into physical contact with the aggressive fluid being conveyed. This is the case for the inner magnet 40 in all exemplary embodiments. For the external magnet 44, this is only the case when the conveying fluid flows around it as a stator 48 and without a hood-shaped cap 24.

Based on the Figure 5 The explained exemplary embodiment of the production of the bearing carrier 22 in the injection molding process means that bearing pieces to be joined separately are omitted and bearing areas are provided as “functional bearings”. Three of these bearings (manufactured in one piece or integrated as a bearing) are provided. Two of these bearing areas guide and support the shaft 10. Another supports the outer rotor 80 of the micropump P.

Already during production by injection molding, the bearings can be integrated into the bearing bracket without the need for additional bearing components (previously called "bearing pieces"). This embodiment is not shown separately, but should be read accordingly.

Claims (19)

1. Pump arrangement with a magnetically drivable micropump (P) for conveying a liquid pumping medium and with a bearing carrier (22) as base part, wherein an outer magnet (44) and an inner magnet (40) are provided, transmitting a rotary motion to the micropump (P) by means of an axial shaft (10), and wherein

   - within the bearing carrier (22) three radial bearing pieces (1, 2, 3) are positioned and defined as bearing for the rotational mounting and guidance of the shaft (10) and the micropump (P), wherein one of the bearings as first bearing (3) rotatably accomodates an outer rotor (80) of the micropump and is arranged eccentrically to the shaft (10);

   - the second bearing (2) is arranged closer to the inner magnet (40) and/or the third bearing (1) is arranged closer to the micropump (P);

   - the micropump (P) is held in the eccentric bearing (3) by a cover (26) arranged at the front;

   - a pressure-side channel structure (23) is provided for a forced flow, the pressure-side channel structure having at least a first channel section (23b) with a radial direction component within the cover (26), at least a first second channel section (23c, 23e) within the bearing carrier (22), and another further axial section (23f) of the pressure-side channel structure (23) leading through the cover (26), the further axial section (23f) also being arranged at the pressure side of the micropump (P);

   - a hermetically sealed casing arrangement (20) is formed out of the bearing carrier (22), a dome-shaped cap (24) and the cover (26), so that the conveyed liquid pumping medium from the pressure side of the micropump is able to cool the dome-shaped cap (24) from the inside via the pressure-side channel structure (23).
2. Pump arrangement according to claim 1, wherein the outer magnet (44) and the inner magnet (40) create a magnetic torque transmission, thus generating a magnetic drive to the shaft (10) and an inner rotor (82) of the micropump (P).
3. Pump arrangement according to claim 2, wherein the movement of the inner magnet (40) is generated by a magnetic field that is created by a rotating outer magnet (44) arranged radially further on the outside.
4. Pump arrangement according to claim 2, wherein the inner magnet is turned by a rotating magnetic field that may be generated by a mechanically not rotating stator in the form of a rotating field, the stator being arranged radially further on the outside.
5. Pump arrangement according to claim 1, wherein the outer rotor (80) is the outer rotor of a gear ring pump (Zahnringpumpe) (P) or an outer rotor of an internal gear pump (Innenzahnradpumpe).
6. Pump arrangement according to claim 1, wherein the inner magnet (40) is arranged on an inner magnet carrier (42).
7. Pumping arrangement according to claim 1, wherein a joining connection of the bearing pieces (1, 2, 3) with the bearing carrier (22) is achieved by means of bonding, soldering or moulding.
8. Pump arrangement according to claim 1, wherein the bearing carrier (22) is produced by means of injection moulding of metal or plastic.
9. Pump arrangement according to claim 8, wherein at least one heating element (71, 72) is integrated in an injection-moulded bearing carrier (22).
10. Pump arrangement according to claim 1, wherein the bearing pieces (1, 2, 3) are separate precision components that are or were positioned and defined within the bearing carrier (22) by means of a joining technique.
11. Pump arrangement according to claim 3, wherein the torque transmission is a concentric rotary coupling (Zentraldrehkupplung).
12. Pump arrangement according to claim 4, wherein the inner and the outer magnet (44, 40) are arranged concentrically.
13. Pump arrangement according to claim 6, wherein the inner magnet (40) is one- or multi-piece, particularly is encapsulated by means of encapsulation or coating.
14. Pump arrangement according to claim 1, wherein the maximum dimensions of the micropump (P) are not larger than 20 mm, particularly 10 mm.
15. Pump arrangement according to claim 1, wherein the pressure-side channel structure (23) for the forced flow has a further second channel section (23e) within the bearing carrier (22).
16. Pump arrangement according to claim 15, wherein the two second pressure-side channel sections (23c, 23e) located within the bearing carrier (22) both substantially extend in an axial direction.
17. Pump arrangement according to claim 1, wherein the pressure-side channel structure (23) has a planar section (23d) extending in a radial direction.
18. Method for conveying a fluid pumping medium, wherein

    - a rotary motion is transmitted to the micropump (P) of the pump arrangement according to claim 1 by means of the axial shaft (10);

    - the magnetically driven micropump (P) for conveying the liquid pumping medium is driven by an outer magnet (44) and an inner magnet (40) being coupled by a magnetic field;

    - a wall of a dome-shaped cap (24) is positioned between the outer magnet (44) and the inner magnet (40) and the inner magnet rotates within the dome-shaped cap (24) and transmits its rotary motion to the micropump (P) by means of an axial shaft (10).
19. Method according to claim 18, with the pump arrangement according to one of the claims 2 to 17.

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