EP0769621A1 - Micropump and micromotor - Google Patents

Abstract

The invention concerns a micropump (1) for the substantially continuous delivery of a mass flow, the micropump having a sleeve axis (101) and an offset axis of rotation (100). An internal rotor (20) meshes with an external rotor (30) in a sleeve (60) and at least one outlet-side pressure opening (42n) in a first end-face insert part (42), which is inserted into the sleeve (60) of slightly largely diameter, is aligned in the axial direction (100). The invention further concerns a micromotor (2) of similar construction in which the diameter of the delivery hose corresponds approximately to that of the sleeve casing (60, 61). The pump and motor are extremely miniaturized yet still permit a continuous flow with high feed pressure and high output.

Description

The technical field of the invention is the smallest size pumps and motors, hereinafter referred to as micropump or micromotor, whereby these terms are understood to mean orders of magnitude that are in the diameter range below 10 mm, in particular below 3 mm. Pumps of this type can be used in a variety of ways in technical and medical fields, for example in microsystem technology in metering devices, in medical technology as a drive for a micro-milling cutter or as a blood flow support pump.

In the prior art there is a wide range of descriptions of the principle and mode of operation of gear pumps with an inner wheel and an outer wheel, whereby these two wheels are in meshing engagement (cf. DE-A 17 03 802 , there claim 1, page 4 last paragraph and page 6, last paragraph, where radially directed inflow and outflow channels are described). Characteristic of these functional units to be used as pumps or motors are two mutually offset axes, one axis of the inner rotor and the other axis of the outer rotor, the two intermeshing rotors circumferentially forming pressure chambers (pressure chambers), which vary in size and location change cyclically.

The object of the invention is to provide a micropump of minimal construction volume, with which a continuous flow of the fluid to be pumped is achieved and nevertheless a high delivery rate or a high delivery pressure is made available.

This is achieved with a micropump when the outlet-side pressure opening of an end-side insert is aligned in the axial direction for a sleeve that is somewhat larger in diameter (claim 1). The inlet opening of the second end insert for the sleeve, which is somewhat larger in diameter, can also be aligned in the axial direction (claim 2). The entire pump can generate a continuous flow of liquid in the axial direction, which is only in the Interior, in the meshing rotors and in the circumferential displacement of the pressure chambers, is oriented in the circumferential direction. As soon as the liquid flow to be conveyed enters the end insert at the outlet end, it is led out from there in the axial direction through a pressure opening which is directed in the axial direction. The pressure opening can consist of a plurality of circumferentially spaced individual bores, it can consist of a bore and it can be formed from a bore together with a kidney-shaped collecting groove provided on the inside of the outlet insert part (claim 3).

The advantage of the pumps according to the invention lies in their simple construction in spite of their almost unimaginable miniaturization, whereby the assembly of the micropump can take place with a manufacturing process (claim 11) in which the largely cylindrical parts are inserted into one another in the uniaxial direction. The two end insert parts come inserted in the axial direction and lie on the two ends of the sleeve shell, while they axially support the intermeshing wheels (inner wheel and outer wheel) also inserted in the (same) axial direction.

The pump is driven e.g. on an extended piece of the axis of the inner rotor (claim 6) or radially over the sleeve in a purely mechanical or electromechanical way (claim 7). For the most extensive miniaturization in the case of electromechanical drives, e.g. the outer wheel or the sleeve have integrated magnets to serve as a rotor of a synchronous drive, the sleeve lying radially further outside allowing the electromagnetic fields to pass through.

Minor delivery losses due to circumferential inaccuracies are advantageously used for mounting the rotatable part in the jacket (claim 8).

A motor for driving the pump mentioned is also characterized by the smallest design, and it has a high power density provides and even has a favorable characteristic curve (torque versus speed) ready. At not too high speeds, the motor reaches a torque with which a pump can be driven without a gear. The drive energy of the engine is generated from a fluidic current that runs through the meshing wheels (inner wheel and outer wheel) and is released into the environment at the outlet end. The drive fluid enters through a supply hose or connecting piece which can be fixedly attached to the sleeve of the insert part or to the insert part itself (claim 9).

When attached to the front insert part, this can be slightly to significantly longer than the sleeve in order to obtain a firm fit for the supply hose.

The attachment of the supply hose implies that the diameter of the supply hose is approximately the size of the diameter of the micromotor, which is described in claim 10.

When using the fluidic drive, there are no difficulties with regard to electrical insulation in the smallest sizes. The fluidic drive medium can simultaneously serve as a cooling medium, lubricant, flushing medium and storage liquid.

The motor (claim 9) is constructed with the same components as the pump (claim 1), only other functional elements are fixed or rotatable. For the motor and for the pump, there are several options for realizing them with a uniaxial insertion into one another (claim 11), depending on which part is fixedly arranged on which part, which part is rotatably arranged on which part and with which part the Arrangement is supported at a fixed point. When driving with a supply hose, the support location will be the supply hose itself. An elongated drive shaft is used when operating the pump by means of an extended shaft section.

Figur 1

ist ein Beispiel für eine Pumpe 1 mit Einsetzteil 41 und Antriebsachse 50.

Figur 1a

ist eine Möglichkeit, die Bauelemente der Figur 1 fest bzw. drehbar zueinander zu gestalten, wobei eine Schraffur eine feste Anbringung andeutet. Flächen, die aneinander angrenzen ohne im Grenzbereich schraffiert zu sein, sind gegeneinander beweglich.

Figur 2

ist ein Beispiel für einen Motor 2 mit verlängertem Einsetzteil 41, auf das ein Zuführschlauch für ein Antriebsfluid gesteckt werden kann.

Figur 2a

ist ein Beispiel der Schaffung zueinander beweglicher oder fester "Grenzzonen" für den Motor der Figur 2, wobei eine Schraffur eine feste Grenzzone andeutet.

Figur 3a, Figur 3b und Figur 3c

zeigen drei radiale Stellungen eines Innenrotors 20 gegenüber einem Außenrad 30, die beide im kämmenden Eingriff stehen.

Figur 4

veranschaulicht eine Seitenansicht einer Hülse 60 mit darin eingesetzten zwei Stirnteilen 41,42, sowie eine Schnittansicht A-A.

Figur 5

ist ein Aufbau, bei dem im praktischen Versuch eine Pumpe 1 in einen Förderkanal geschaltet ist, der von einem Saugende S zu einem Druckende D führt. Gewählt ist hier eine umfängliche Antriebsrichtung an der Hülse 60 der Pumpe 1.

Figur 6a, Figur 6b und Figur 6c

zeigen Anschlußmöglichkeiten für einen Schlauch SH, mit dem Fluid für den Antrieb des Motors 2 zugeführt wird. Der Schlauch ist undrehbar befestigt.

Figur 7a, Figur 7b, Figur 7c und Figur 7d

zeigen Anschlußmöglichkeiten für einen Antrieb A entweder an der Welle 50 oder am Einsetzteil 41 oder am Außenmantel 60 mit einem umfänglichen Antrieb 63a,63b, wie er im Aufbau in der Figur 5 verdeutlicht ist. Figur 7b ist ein elektromechanischer Antrieb nach dem Prinzip des Synchronmotors.

Figur 8

veranschaulicht in drei Skizzen A, B und C drei unterschiedliche Ausgestaltungen von Einlaß- oder Auslaßöffnungen 41n,42n in den Stirnteilen 41,42 gemäß Figur 1.

The invention is explained and supplemented below using several exemplary embodiments.

Figure 1

is an example of a pump 1 with insert 41 and drive shaft 50.

Figure 1a

is a way to make the components of Figure 1 fixed or rotatable to each other, a hatching indicates a fixed attachment. Surfaces that are adjacent to each other without being hatched in the border area are movable against each other.

Figure 2

is an example of a motor 2 with an extended insert part 41, on which a supply hose for a drive fluid can be plugged.

Figure 2a

is an example of creating mutually movable or fixed "boundary zones" for the motor of Figure 2, with hatching indicating a fixed boundary zone.

Figure 3a, Figure 3b and Figure 3c

show three radial positions of an inner rotor 20 relative to an outer wheel 30, both of which are in meshing engagement.

Figure 4

illustrates a side view of a sleeve 60 with two end parts 41, 42 inserted therein, and a sectional view AA.

Figure 5

is a structure in which, in a practical experiment, a pump 1 is connected into a delivery channel which leads from a suction end S to a pressure end D. A circumferential drive direction on the sleeve 60 of the pump 1 is selected here.

Figure 6a, Figure 6b and Figure 6c

show connection options for a hose SH, with the fluid for driving the motor 2 is supplied. The hose is non-rotatably attached.

Figure 7a, Figure 7b, Figure 7c and Figure 7d

show connection options for a drive A either on the shaft 50 or on the insert part 41 or on the outer casing 60 with a circumferential drive 63a, 63b, as is illustrated in the structure in FIG. Figure 7b is an electromechanical drive based on the principle of the synchronous motor.

Figure 8

illustrates in three sketches A, B and C three different configurations of inlet or outlet openings 41n, 42n in the end parts 41, 42 according to FIG. 1.

FIG. 1 shows a schematic sketch of a micropump 1, which is of an order of magnitude of less than 10 mm in diameter, but which, in particular, can be reduced to orders of magnitude which are less than 2.5 mm in diameter using the wire and die-sinking EDM method. With an outer diameter of 2.5 mm, the length of the pump is only about 4 mm, measured in the axial direction 100.

Other manufacturing processes can also be used, such as LIGA technology, plastic injection molding, ceramic injection molding, extrusion molding, metal sintering or micro-milling or turning, or general micro-machining.

The micropump 1 consists of a sleeve 60, in which five functional elements are partially movable and partially firmly integrated, whereby in the case of "fixed integration" functional elements that do not have any relative movement to one another execute or their function requires a fixed connection can also consist of a part, if the production permits. An end insert 41 and 42 is provided on each end face of the sleeve 60, both of which have an eccentric bore for receiving a pump axis 50. The bores are aligned along a first axis 100, which is slightly offset radially outward with respect to the central axis 101 of the sleeve 60.

The two end inserts 41, 42 are axially spaced and between them two rotatable and intermeshing rotors are provided, an outer rotor part 30 and an inner rotor part 20. The inner rotor 20 has outwardly directed, circumferentially evenly spaced teeth. The teeth mesh with the outer rotor part 30, which has inwardly open longitudinal grooves 30a, 30b, ... which are evenly spaced around the circumference and match the shape of the teeth of the inner rotor 20 so that each tooth of the inner rotor has a meshing rotational movement forms in the axial direction sealing line on the inner surface of the associated groove 30a, 30b, ... of the outer wheel 30. All sealing lines move in the drive direction A about the axis 100, the delivery or pump chambers 20a, 30a; 20b, 30b (etc.) defined between two sealing lines moving during the rotational movement towards the outlet bore 42n in FIGS 3c, reduce the volume shown on one half of the pump, and on the opposite half, to give a repeating cycle from minimum to maximum chamber volume and back.

The inner wheel 20, together with the drive axis 50, describes a rotational movement, a drive can couple in a rotary movement A via a longer flexible shaft, and an electric drive can also be arranged directly on the axis 50.

An example of the definition of fixed boundary zones (closely adjacent areas of two adjoining parts of the pump) is shown in FIG. 1a. Hatches indicate a fixed (not rotating) border zone, the other border zones allow a rotating movement of the adjacent parts.

While the axis of rotation 50 together with the fixed inner wheel 20 and the outer wheel 30 are rotatable in the sleeve 60, the other parts of this example are the micropump - the end inserts 41, 42 and the sleeve 60 extending over the length of the pump 1 - extensively firmly connected. The axis 50 is rotatably supported in the bores of the end inserts 41, 42, and the outer wheel 30 is likewise rotatably supported in the fixed sleeve 60. Thus, when rotating, the axis 50 according to FIG. 1a, represented by an angular velocity vector A, both move the outer wheel 30 as well as the inner wheel 20 with rotational movement of the sealing lines according to FIG. 3 and simultaneous rotation of the changing chamber volumes 20a, 30a (etc.) between the outer wheel and the inner wheel.

The fixed border zones can e.g. be made by gluing.

The chamber volumes become smaller in the direction of the smallest distance between the axis 100 of the axis of rotation 50 and the sleeve 60, whereby the liquid conveyed therein is put under increased pressure, while on the other hand, after the smallest distance between the axis 100 has been exceeded and enlarge the inner surface 61 of the sleeve 60 again.

Together with kidney-shaped openings 41n, 42n in the end faces 41, 42, which are arranged in such a way that their smallest radial width begins at the point at which the distance between the axis 100 and the inner jacket 61 of the sleeve 60 is the smallest, while If its maximum radial width is at the location which is close to the greatest distance from axis 100 to the inner lateral surface 61 of the sleeve 60, a feed pump is obtained. The inflow kidney 41n, which is on the inflow side of the liquid V 'to be conveyed, is mounted in the opposite direction to that outflow kidney 42n, which is shown in the aforementioned FIG. 1a at the outflow location of the delivery volume V conveyed under pressure. FIG. 1a therefore shows an outflow kidney 42n on the outflow side, which widens radially in the direction of rotation A of the pump shown from the smallest distance of the axis 100 to the greatest distance of the axis 100 from the inner lateral surface 61, while the inflow Kidney 41n is located in the end insert 41 and is reduced in its radial extent with its greatest radial width from the location of the greatest distance of the axis 100 to the inner lateral surface 61 of the sleeve 60 to the smallest distance of the axis 100 from the inner lateral surface 61 of the sleeve 60.

• Ein Kurzschluß der Förderung, d.h. eine durchgehende Verbindung zwischen der Einlaß-Niere und der Auslaß-Niere wird in allen Drehpositionen verhindert; damit wird die umfängliche Erstreckung der Nieren 41n,42n definiert.
• Der Ein- und Auslaßquerschnitt der Nieren - die radiale Abmessungsveränderung - orientiert sich an dem Fußkreisdurchmesser des Außenrades 30 und dem Fußkreisdurchmesser des Innenrades 20, wobei die Querschittsfläche so groß als möglich gewählt werden sollte, um geringen Druckverlust zu erhalten, allerdings bei Einhaltung der erwähnten Dimensionierungsvorschrift.

The dimensions and the change in width of the two kidneys 41n, 42n are matched to the following criteria:

• A short circuit in the delivery, ie a continuous connection between the inlet kidney and the outlet kidney is prevented in all rotational positions; this defines the circumferential extent of the kidneys 41n, 42n.
• The inlet and outlet cross-section of the kidneys - the radial change in dimension - is based on the root diameter of the outer wheel 30 and the root diameter of the inner wheel 20, the cross-sectional area should be chosen as large as possible in order to obtain low pressure loss, but while observing the dimensioning instructions mentioned .

The two kidneys can also be introduced as curved grooves 41k, 42k in the inner flat wall of the end faces, in which case a cylindrical bore 41b, 42b is provided as an outlet and an inlet in the axial direction of the pump. This increases the stability, which is not unimportant given the small component sizes. Different possibilities of the inlet kidney and outlet kidney are shown in FIG .

One-off production of the pump, which consists of only six (or fewer) components, is advantageously possible with the wire and sink erosion mentioned, with all pump parts included Cylinder coordinates can be adequately described, which means for production that one dimension does not require any additional processing. The end inserts 41 and 42 can be manufactured with wire erosion. The axis 50 is cylindrical anyway, the inner rotor 20 can also be manufactured with wire erosion, just like the outer rotor 30. The sleeve 60 is also a pump component that can be manufactured with wire erosion.

If the kidney-shaped inlet and outlet grooves 41k, 42k mentioned above are produced in the inner sides of the end inserts 41, 42, die-sinking erosion can be used for this.

Sintered or hard metal is recommended as the material for the manufacture of the micropump, which is low-warpage and fine-grained, can be easily machined with wire and die erosion and is largely medically compatible. In medical terms, a ceramic material is cheaper, but it can only be processed in large quantities and is not so suitable for the production of individual functional samples. If the erosion processes are used, attention must be paid to the electrical conductivity of the material, a ceramic injection molding process is used - with molds that e.g. can be produced by wire and sink erosion - so the electrical conductivity of the material of the micropump is no longer necessary. For large quantities, plastic, metal or ceramic injection molding processes can be used.

The pump 1 described with reference to FIGS. 1 and 1a and the manufacturing process can be used without any problems in medical applications such as catheters. The drive A mentioned can be made by a thin, bendable shaft. The drive of the micropump can also be achieved by a liquid-driven motor 2, which is manufactured in the same way and has the same appearance as the pump 1 described, only for the motor 2 a fluidic drive through the inflow kidney 41n selected with a hose SH, which is fixedly arranged on the end insert 41 (Figures 2.2a). Since the sleeve 60 in the fluidic micromotor 2 is fixedly attached to the outer wheel 30 - for example by gluing or a snug fit or by a welded or soldered connection - the sleeve 60 is rotated and its output force A 'can be transmitted to the pump 1 as drive force A. . The output A 'of Figure 2a is mechanically rigidly coupled to the drive axis 50 of the pump 1 of Figure 1a.

The pump 1 can be driven via the sleeve 60 instead of via the shaft 50 with the direction of rotation A, as is shown in FIGS. 7c and 7d using examples. It is also possible to reverse the drive direction in order to then also achieve the delivery effect of the micropump in a delivery direction from V to V '.

If all of the above-mentioned pump parts with cylinder coordinates can be adequately described, they can also be mounted in an axial direction, with the six basic components of the pump 1 or the motor 2 being joined together only in this axial direction (uniaxially) and in certain predetermined areas (in the previously mentioned border zones) are mechanically rigidly connected or remain movable. This uniaxial mounting option offers advantages for automated series production, which is desirable with such a small construction volume.

The concepts of a pump 1 or a motor 2 shown in FIGS. 1 and 2 are specified in FIG. 1 a or in FIG. 2 a for an exemplary embodiment, border zones being shown hatched, which show a firm (for example adhesive or form-fitting) connection, while those interfaces between two components that do not have hatching are rotatable relative to one another. In FIG. 1a, the two end inserts 41, 42 are rigidly connected to the sleeve 60 on its inner jacket 61. In the pump according to FIG. 2a, these boundary zones are designed to be rotatable. In the pump according to FIG. 1a there is a further fixed connection between the axis 50 and the inner wheel 20 provided, this connection is in turn rotatable in the motor according to FIG. 2a, instead in the motor in FIG. 2a the boundary zone between the sleeve 60 and the outer wheel 30 is connected in a rotationally rigid manner, which boundary zone in the pump 1 according to FIG. 1a is rotatable.

Further possibilities for motor 2 result from FIGS. 6a, 6b and 6c; further possibilities for pumps result from FIGS. 7a, 7b, 7c and 7d.

FIG. 6a shows a fluidic motor which receives drive fluid V via a hose SH. The hose is firmly attached in an axis 101 to the end insert 41 (base support or base part). The base carrier 1 does not rotate, instead, the inner wheel 20 and outer wheel 30 rotate, the latter taking the sleeve 60 with them. The hose SH is mechanically immovably supported at position 44, for example. The structure of FIG. 6a corresponds to that of FIG. 2a, in which the hose SH has not yet been shown. The base part 41 is axially extended for attaching the hose SH in order to obtain an easy plug-on possibility. The diameter of the hose and base part is accordingly the same, the hose for supplying the fluid V accordingly has an order of magnitude in the diameter direction which corresponds to that of the motor 2. The output and thus the driving force takes place via the sleeve 60; the axis of rotation is accordingly the sleeve axis 101.

In FIG. 6b , the hose SH is firmly supported with respect to the surroundings, indicated schematically by the reference number 51. The fixed support can also be provided by the inherent stiffness of the hose SH, without a fixed support being required directly for the motor 2. The hose SH is plugged onto the sleeve 60 here, the output takes place via the axis 50, the axis of rotation being the axis 100. For this embodiment, the axis 50 is extended in the axial direction in order to mechanically couple the output. With regard to the hatched border zones and the related torsionally rigid attachment, reference is made to the referenced above.

In FIG. 6c , the hose SH is also coupled to the sleeve 60, alternatively to an end insert 41 which is extended towards the rear. The output takes place here via an axially extended cover 42, which is the second end insert on the front end of the pump 2. The axis of rotation is the axis 101 (sleeve axis), the axis 50 wobbles slightly, ie the axis of rotation 100 moves on a circular path.

FIG. 7 a corresponds to the pump variant of FIG. 1 a, a shaft 58 being provided which applies rotary coupling d to the axially elongated axis 50. The axis of rotation is 100 (axis of the shaft 50), the sleeve 60 is stationary and is mechanically rigidly coupled at 51. In FIG. 7a, the inner wheel 20 and outer wheel 30 rotate in the sleeve 60. Rigid in the sleeve 60 are the two end inserts 41 and 42, which do not have to be extended axially.

FIG. 7b shows a coil arrangement 63 which couples an electromagnetic field into the pump 1. The rotor of this example designed as a synchronous motor is the outer wheel 30, which can be designed, for example, as a permanent magnet. For this embodiment, the sleeve 60 must be arranged in a fixed manner and at the same time allow electromagnetic fields to pass through, for example, be made of plastic or ceramic. The outer wheel 30 and the inner wheel 20 in the sleeve 60 can be rotated in FIG. 7b. The bearings of the two rotors 20, 30 in the end inserts 41, 42, which in turn are firmly attached to the Sleeve 60 are arranged. The axis of rotation for the outer wheel 30 is the sleeve axis 101, the axis of rotation is the axis 100 of the axis of rotation 50. The inlet 41n and the outlet 42n are immovable in the circumferential direction and thus at a radially defined point.

FIG. 7c illustrates a mechanical drive mode via a pinion or drive wheel 63a, which is circumferentially connected to the sleeve 60 in the attacks essentially slip-free. The axis of rotation of the arrangement is the sleeve axis 101. The end-face insert 41 stands still and is extended in the axial direction for mechanical fastening 44. The outer wheel 30 is arranged fixedly on the sleeve 60 and its inner casing 61. The inner wheel is rotatably mounted on the axle 50, while the axle 50 itself is arranged in a rotationally rigid manner on the two end inserts 41, 42, which in turn are rotatably supported on the inner jacket 61 of the sleeve 60. In this construction of the pump 2 in FIG. 7c, the practical testing was carried out using FIG. 5, in which a circumferential cylinder ring 63a was used as the drive wheel or pinion.

FIG. 7d illustrates the drive on the axially elongated end insert 41 with an alternative drive wheel or pinion 63b, the sleeve being mechanically firmly anchored at 51. The axis of rotation is the sleeve axis 101, the axis 50 wobbles slightly, ie the axis of rotation 100 of the axis 50 moves on a circular path.

Just as a pump driven electromagnetically according to the synchronous principle is shown in FIG. 7b, FIG. 7d can be converted into such a synchronous variant with the mechanical engagement pinion 63b, the base carrier 41 being given a corresponding permanent magnet design. The sleeve 60 is then free with regard to its metallic or non-metallic design.

The principle of operation of FIGS. 3 with the several circumferential sealing lines, which delimit individual delivery chambers between them, which enlarge on one half side of the pump (suction side) and decrease on the opposite half side from a maximum (pressure side), is a side view in FIG Figure 4 can be seen again. The sleeve 60 carries the two end inserts 41, 42 concentrically and between the end inserts 41, 42 the rotors 20 and 30 are shown, which were shown in FIG. 3 to define the sealing lines in supervision. The schematic in Figures 3 Inlet kidney 41k and outlet kidney 42k shown are rotated in the sectional plane in FIG. 4, so that it can be seen that they lead directly to the outwardly facing end faces of the rotor parts 20, 30. The torsionally rigid attachment between the axle 50 and the inner wheel 20 takes place via a flattened portion 50f which, in addition to an adhesive attachment, can provide positive force transmission.

It was already explained with reference to FIG. 7c how the pump is constructed, which was tested in FIG. 5 in a practical test setup with regard to its performance values and characteristic data. This pump can be seen in the center of FIG. 5, an inflow path and an outflow path lead from the suction side S via the supplied fluid V 'to be pumped via the pump 1 to a pressure side D on which the fluid V has an increased pressure. Pressures that could be achieved with this pump structure were at a differential pressure of about 50 bar, at a pump output of 200 ml / min, whereby it should be added that the dimensions of the pump 1 were in the order of 10 mm outside diameter of the sleeve 60 .

It should be mentioned in relation to FIG. 5, which is self-explanatory that the drive sleeve 63a was firmly coupled to the sleeve 60 of the pump and drive power was transmitted to the pump via a drive tube 77, which is correspondingly mounted centrally. On the end inserts 41, 42, which were axially extended, adapter sleeves are arranged which, according to FIG. 7c, serve for the rotationally fixed mounting of these end insert parts 41, 42. A strain gauge DMS 74 is placed around the feed pipe 71 for the measurement. Bores 73 in the measuring structure serve to determine leaks during conveying and the drive 76 is shown schematically with engagement with the drive tube 77.

With FIG. 5, basic data and performance limit values of pump 1 could be tested.

In the fluidic micropump 1, the liquid is pumped through a rotating displacement piston 30/20, which changes its chamber volumes by rotation such that liquid can be continuously sucked in through the inlet 41n and continuously ejected on the outlet side 42n. In contrast to most other pump systems of the prior art, the invention also enables the reverse operation as a fluidic motor.

Because of the fluidic energy transfer, the systems proposed here are characterized by a high power-to-weight ratio, high pressures that can be generated, high output torques and high flow rates.

The wire erosion and die sinking erosion processes can be used as the manufacturing processes for such motor / pump systems for prototypical realizations. The current wire EDM machines work with resolutions of 0.5 µm and achieve contour tolerances of 3 µm with surface roughness of at least R _a = 0.1 µm. Even more precise and finer machines are currently under development. On the one hand, the eroding processes can be used directly for the production of prototypes of micropumps / motors, on the other hand, molds and tools for the production of parts according to alternative manufacturing processes (ceramic, metal, plastic) can be mass-produced. The alternative manufacturing processes mentioned for the production of the motor and pump components can be extrusion, fine sintering, injection molding or die casting. Other manufacturing processes, such as the LIGA process, also appear to be suitable.

• 
  Kostengünstige und einfache Herstellung von Einzelteilen oder Kleinserien
• 
  Große Breiten/Höhenverhältnisse (Aspektverhältnisse bis maximal 12 mm; im Vergleich zu dem LIGA-Verfahren: 1 mm)
• 
  Schräge Wandungen von bis zu 30° möglich
• 
  Bearbeitung sehr unterschiedlicher und harter Materialien möglich, sofern sie elektrisch leitfähig sind, wie bspw. Hartmetall, Silizium und elektrisch leitfähige Keramiken.
• 
  Technologie mit geringem technologischem Risiko.

The production by eroding yields the following results:

• 
  Inexpensive and simple production of individual parts or small series
• 
  Large width / height ratios (aspect ratios up to a maximum of 12 mm; compared to the LIGA process: 1 mm)
• 
  Sloping walls of up to 30 ° possible
• 
  Machining of very different and hard materials possible, provided they are electrically conductive, such as hard metal, silicon and electrically conductive ceramics.
• 
  Technology with low technological risk.

• 
  Einfacher Aufbau
• 
  robust, unempfindlich gegenüber Verschmutzungen
• 
  Keine Ventile notwendig
• 
  Direkt umkehrbare Pumprichtung bzw. Drehrichtung des Motors
• 
  Hohe Antriebsmomente
• 
  Hohes Leistungsgewicht
• 
  Relativ starre Drehmoment/Drehzahl-Kennlinie
• 
  Antriebsmedium (Fluid) beim Motor kann zum Kühlen oder Spülen verwendet werden
• 
  Keine elektrischen Verbindungen notwendig (bspw. in exgeschützter Umgebung oder bei Gehirn- und Herzoperationen).

The advantages of hydraulic micromotors and micropumps:

• 
  Easy construction
• 
  robust, insensitive to dirt
• 
  No valves necessary
• 
  Directly reversible pump direction or direction of rotation of the motor
• 
  High drive torques
• 
  High weight to performance ratio
• 
  Relatively rigid torque / speed characteristic
• 
  Drive medium (fluid) in the motor can be used for cooling or flushing
• 
  No electrical connections necessary (e.g. in an explosion-protected environment or during brain and heart operations).

• 
  Mikrohydraulikaggegat: duch Kopplung der Mikropumpe mit einem Motor zur Erzeugung hydraulischer Energie
• 
  Analyse-/Dosierpumpe: zur Entnahme bzw. Abgabe genau definierter Flüssigkeitsvolumina in Chemie, Medizin, Lebensmittelindustrie, Maschinenbau
• 
  Volumenzähler/Strömungsmesser: Anwendungen in der Meßtechnik
• 
  Heizungsbrennerpumpe
• 
  Antrieb eines Mikrofräsers für medizinische und technische Anwendungen
• 
  Endoskopantrieb
• 
  Dilatationskatheter mit integrierter Mikropumpe zur Aufrechterhaltung des Blutstroms während der Ballondilatation
• 
  Medikamentierungskatheter mit intergrierter Mikropumpe zur Aufrechterhaltung des Blutstroms während der Medikamentierung (bspw. Lysebehandlung)
• 
  Blutstromunterstützungspumpe
• 
  Verstellaggregat für Ultraschallspiegel (Transducer) in Kathetern
• 
  Antrieb für ein rotierendes Schneidwerkzeug an Endoskopen, Kathetern
• 
  Miniaturgenerator: durch Kopplung der fluidischen Mikropumpe mit einem elektrischen Miniaturgenerator zur Erzeugung elektrischer Energie
• 
  Pumpen für fluidische bzw. hydraulische Mikrosysteme
• 
  Kompressor für ein Miniaturkühlaggregat: bspw. zur Kühlung von Prozessoren)
• 
  Antriebselemente für große Stellkräfte
• 
  Sonnenblendschutz: in Mehrfachscheiben wird lichtdämpfende Flüssigkeit zwischen die Scheiben gepumpt.

Fields of application of the micropump or the fluidic micromotor:

• 
  Micro hydraulic unit: by coupling the micro pump with a motor to generate hydraulic energy
• 
  Analysis / dosing pump: for taking or dispensing precisely defined liquid volumes in chemistry, medicine, food industry, mechanical engineering
• 
  Volume counter / flow meter: Applications in measurement technology
• 
  Heating burner pump
• 
  Drive of a micro router for medical and technical applications
• 
  Endoscope drive
• 
  Dilatation catheter with integrated micropump to maintain blood flow during balloon dilation
• 
  Medication catheter with integrated micropump to maintain the blood flow during medication (e.g. lysis treatment)
• 
  Blood flow support pump
• 
  Adjustment unit for ultrasound mirrors (transducers) in catheters
• 
  Drive for a rotating cutting tool on endoscopes, catheters
• 
  Miniature generator: by coupling the fluidic micropump with an electrical miniature generator to generate electrical energy
• 
  Pumps for fluidic or hydraulic microsystems
• 
  Compressor for a miniature cooling unit: e.g. for cooling processors)
• 
  Drive elements for large actuating forces
• 
  Sun protection: in multiple panes light-absorbing liquid is pumped between the panes.

The contour of the wheels 20, 30 is the equidistant of an epi- or hypocycloid and is calculated using a generally known approach.

• 
  Basisträger (erster Stirneinsatz) 41
• 
  Achse 50
• 
  Deckel (zweiter Stirneinsatz) 42
• 
  Innenrad 20
• 
  Außenrad 30
• 
  Hülse 60.

The basic components of the micropump consist of the following components:

• 
  Base support (first forehead insert) 41
• 
  Axis 50
• 
  Lid (second forehead insert) 42
• 
  Inner wheel 20
• 
  Outer wheel 30
• 
  Sleeve 60.

In the micropump 1, the inner wheel 20 is firmly connected to the axle 50 according to FIG. 2a. Likewise, cover 42 and base support 41 are firmly connected to one another via sleeve 60. The connections can be in the form of an adhesive connection, a press fit, a welded or soldered connection, etc. The pump 1 is driven by rotating the axis 50, for. B. by an electric micromotor, a fluidically driven micromotor 2 according to FIG. 2a or by a flexible shaft 58 according to FIG. 7a. As a result, depending on the direction of rotation, liquid is pumped from the base part 41 to the cover 42 or vice versa.

In the micromotor 2 according to FIGS. 2, 2 a, the base part 41 and cover 42 are firmly connected to the axis 50. In addition, the outer wheel 30 is connected to the sleeve 60. To operate the engine, a fluid is supplied under pressure on the inflow side of the base part 41. As a result, the sleeve 60 (output) rotates about its axis 101. The fluid leaves the micromotor on the outflow side with less pressure than on the inflow side. The pressure difference minus losses is converted into mechanical energy. A reversal of the pressure and discharge side causes a reversal of the direction of rotation A 'of the motor.

The function of the micropump 1 and the micromotor 2 is based on the displacement principle. Here, the working spaces 20a, 20b increase and decrease cyclically, as explained in FIGS. 3.

In the micromotor 2, a fluid flows under high pressure into the enlarging work space and, due to the pressure difference between the inlet and outlet, causes a torque on the wheels 20, 30. In the micropump 1, the wheels 20, 30 are driven. The fluid is sucked in by the enlarging work space and brought to a higher pressure level in the shrinking work space. The micropump 1 is driven with the aid of a small electric motor or the fluidic micromotor 2. Further drive options are provided by appropriate shafts.

When pumping according to FIGS. 3, the fluid flows into the pump chamber 20a, 30a via the suction side, and the fluid is pressed out via the pressure side. For clarification, a tooth of the inner wheel is marked with a black dot in FIGS. The pump principle is simply reversed for the micromotor. When operating as a motor, a high pressure is introduced via the inflow into the chamber 20a, 30a on the inflow side, which acts on the tooth flanks and generates a force which is greater than the counterforce on the outlet side, since there is a lower pressure there. The resulting torque drives the motor.

Modifications

• 
  The pump 1 can also be driven via the sleeve 60 instead of via the shaft 50 (FIGS. 7c, 7d). This has the advantage that the sleeve 60 can be driven via a rigid drive, whereas a flexible connecting piece is used for driving the shaft 50, which tumbles.
• 
  The output A 'of the motor 2 can also take place on the shaft 50 instead of on the sleeve 60. The output is connected via a flexible connector or a cardan shaft. The advantage of this output is that the outflowing drive fluid does not have to flow through a possibly connected tool, but can exit or be returned behind it.
• 
  To compensate for the axial gap between the combination inner / outer wheel 20, 30 and the adjoining base part 41 and cover 42, additional compensation pockets 41k, 42k can be attached to the base part 41 and cover 42 (axial gap compensation).
• 
  The bores 41d, 41e, 41f, 41g, 41h in the base part and cover, through which the liquid enters and exits, can also be connected to one another in the form of a kidney 41n, 42n in the case of sensitive fluids (e.g. blood) in Figure 8 with 41n.
• 
  For reasons of reduced friction, instead of a plain bearing, a hydrodynamic bearing can also be used for the fluidic micromotor 2. The liquid for the bearing is supplied from the inflow side.
• 
  As a further option to reduce friction, miniature ball bearings, roller bearings or stone bearings can also be used instead of plain bearings.
• 
  The friction can also be reduced by surface coating the components with a friction-reducing layer, for example graphite or Teflon.
• 
  The principle of operation of the motor 2 results in a one-sided deflection of the axis 50. The resulting one-sided radial gap can be compensated for by radial gap compensation.
• 
  For medical applications, a physiological liquid such as saline or blood plasma can be used as the drive medium for the micromotor 2.
• 
  The fluidic micromotor / pump can be provided with an angle encoder made of optical fibers for speed control or rotation angle detection, which scan the positions of the teeth of the inner and outer wheel 20,30. This enables an exact detection of the rotation angle of the motor or the pump and an exact regulation of the speed.
• 
  The speed control or angle of rotation detection can alternatively take place via an integrated pressure sensor, which measures the pulsation of the chamber pressure and thus transmits the angle of rotation to the control.
• 
  As a complete microsystem, the micropump 1 or the micromotor 2 can be provided with a pressure sensor and associated control electronics. In addition, on / off / overpressure / pressure limiting or check valves can also be integrated. By creating fluidic, electrical and optical interfaces, a completely closed microsystem can be created.
• 
  Alternative manufacturing processes are fine sintering (metal, ceramics), extrusion, wire, die sinking, die casting, injection molding, micro machining, laser cutting. A process that works in multiple ways should be used for cost-effective production. Through the production Large quantities and the use of automated assembly processes, the micropumps or micromotors can be inexpensively similar to chips, u. U. even as a disposable item, because the material and energy consumption are relatively low.

The inlet and outlet take place in the fluidic micropump 1 or in the micromotor 2 in the direction of the axis of rotation 50. This is because the motor can simultaneously serve as a tool holder and the fluid is then supplied from the other side. This structure for the pump and motor is tailored to medical applications and enables a very small cross-section. In the case of a different construction, it is of course also possible to have lateral flow openings through deflection guides.

Furthermore, this design enables the smallest possible total number of parts for the micropump and motor. All components of the pump can therefore be manufactured as 2½-D structures (prismatic shape, which is created by extruding a flat curve into the room).

The fluidic micromotor 2 is an open system. The drive medium (fluid) freely exits the outlet 42n into the working environment. Since the system is not encapsulated, the leakage losses at the bearing points also flow freely into the working environment. The term "open system" is based closely on the above structure with very few parts. Known embodiments encapsulate the entire system, whether motor or pump, due to the use of oil as an energy source. In the present embodiment, it is assumed that the drive medium or the pumped fluid can be released into the environment. In the case of medical systems, this allows the tool to be cooled and the machining site rinsed, which can also be used in technical systems (for example, drilling tools, etc.).

When constructing the open system, sufficient bearing gap lengths should be provided between the base part 41, cover 42 and the rotating sleeve 60, which prevent false air from being sucked in due to the labyrinth seal effect.

Furthermore, the open structure allows the implementation of simple hydrodynamic bearings, base part sleeve and cover sleeve.

The sleeve 60 of the micromotor 2 is supported by the bearing, consisting of the base part 41 and cover 42. Conventional systems are mostly supported by the surrounding housing. There is a closed power flow in the latter. In the proposed motor 2, there is a fixed connection between the so-called base part 41 and the cover 42 via the axis 50, which firmly and rigidly connects the two parts to one another.

The base 41 and the cover 42 and the axis 50 connecting them are secured against rotation by means of axle flattening and / or adhesive securing. Other joining techniques welding, soldering, shrink connection by heating the sleeve and cooling the lid and base part are also possible.

The pump direction is reversed by simply reversing the direction of rotation of the drive. The same applies to the motor: By changing the pressure and suction side, the direction of rotation of the motor is reversed.

The special construction according to FIG. 1a of the micropump and according to FIG. 2a of the micromotor permits both operation as a motor and operation as a pump if the system is driven externally when the pump function is active (shaft in FIG. 1a and sleeve in FIG. 2a) becomes.

The sleeve 60 of the micromotor can be used directly as a tool holder. An example of this can be a milling tool. This tool is hollow on the inside and has an integrated flush, which can be used for cooling or chip removal.

The systems can be expanded with an optical fiber for speed detection or control. For this purpose, the rotating teeth 20a, 20b are scanned at one point, so that both the rotational speed and the rotational angle can be detected incrementally.

The micromotor 2 is intended in particular for medical applications. It can be used as a carrier for cutting tools, milling tools, sensors (especially ultrasonic sensors, mirrors, etc.), actuators for endoscopes and other medical instruments to be moved. When used in medical systems, the micromotor has advantages with regard to its body-compatible drive medium; There are no electrical components that generate electromagnetic fields when they are used and thus have negative effects on nerve conduction, etc. to have; Hydraulic components have the highest power densities and thus lead to the smallest sizes.

Due to their design, the fluidic micromotor and the micropump are easy to clean and, if necessary, sterilize and are therefore well suited for use in medicine.

In applications where the highest level of tightness is not important, the components can be manufactured with a relatively large clearance, which allows the use of cost-effective production technologies such as injection molding. These systems can then be used as single-use items.

The drive medium (fluid) can be used as cooling, lubrication or flushing.

The openings on the inlet and outlet side can be designed in various forms as shown in FIG. The shape of a continuous kidney 41n is possible (A in FIG. 8), which is introduced into the base part 41 and cover 42. This shape can alternatively be approximated by bores 41d, 41e, 41f ... 41h (B in FIG. 8), which increases the stability of these components The consequence is that the webs between the bores 41d to 41h significantly increase the strength. The diameters of the circumferentially aligned bores 41d to 41h are continuously increasing.

Another alternative is to make a single through bore 41b in combination with a kidney-shaped recess 41k (C in FIG. 8), which does not mean a very large weakening in strength, but on the other hand ensures a sufficiently large flow. In particular in medical applications in which blood is pumped, the blood cells are spared because the risk of shearing is significantly reduced.

The shapes shown in FIG. 8 on the inlet side of the base support 41 apply equally to the outlet side (cover 42).

A micropump (1) for the largely continuous delivery of a mass flow is proposed, which has a sleeve axis (101) and an offset axis of rotation (100), in which an inner rotor (20) with an outer rotor (30) in meshing manner in a sleeve (60) Are in engagement, whereby at least one outlet-side pressure opening (42n) of a first end-side insert (42), which is inserted into the sleeve (60), which is somewhat larger in diameter, is aligned in the axial direction (100). In the same design, a micromotor (2) is proposed, in which the diameter of the feed hose corresponds approximately to the size of the sleeve shell 60, 61. Pump and motor are extremely miniaturized, nevertheless they allow a continuous flow with high delivery pressure and high delivery rate.

Claims (12)

Micropump (1) for largely continuous delivery of a mass flow, which pump has a sleeve axis (101) and an offset axis of rotation (100), in which (a) an inner rotor (20) is in meshing engagement with an outer rotor (30) in a sleeve (60); characterized in that (b) at least one outlet-side pressure opening (42n) of a first end-side insert (42), which is inserted into the sleeve (60), which is slightly larger in diameter, is aligned in the axial direction (100, 101). Micropump according to Claim 1, in which the inlet suction opening (41n) of a second end-side insertion part (41) at the other end of the sleeve (60) is (also) aligned in the axial direction (100, 101). Micropump according to one of the mentioned claims, in which a kidney-shaped groove (41k, 42k) is provided on the inside of each of the end insert parts (41,42), which groove in a large part of half of the delivery chambers (30a, 20a) open between the inner rotor and outer rotor (20,30). Micropump according to one of the above-mentioned claims, in which the insert parts (41, 42) adjoin or lie largely tightly with their inner end faces on the outer end faces of the inner rotor (20) and outer rotor (30). Micropump according to one of the mentioned claims, in which the inlet opening (41n) and the outlet opening (42n) lie axially opposite one another, but are offset or rotated radially relative to one another by approximately 180 °. Micropump according to one of the mentioned claims, in which the axis of rotation (50) is longer on one side in the axial direction (100) in order to form a coupling for a mechanical torque (A). Micropump according to one of the claims 1 to 5 mentioned, in which one of its parts which are directly accessible from the outside or indirectly by electromagnetic fields, in particular the outer rotor (30) or the sleeve (60), can be driven in rotation electromechanically (63a, 63b) or mechanically (63) are. Micropump according to one of the claims mentioned, in which low delivery losses on the inner circumference (61) of the casing (60) are used as rotary bearings, resulting from a slight difference in diameter or manufacturing tolerances. Motor for driving a pump according to one of the claims mentioned or for rotating a tool, such as micro-milling cutter, in the (a) an inner rotor (20) is in meshing engagement (20a, 30a) with an outer wheel (30), both of which are arranged on the end face by insert parts (41, 42) in a longer sleeve (60), the axis (100 ) of the inner rotor (20) and the axis of the sleeve (101) are offset in parallel; (b) a supply hose (SH) can be fixedly attached to the sleeve (60) or one (41) of the insert parts (41, 42) in order to supply a drive fluid (V) through an axial inlet opening (41n) to one of the insert parts (41) to guide the meshing wheels (20, 30). Motor or pump according to one of the preceding claims, which are manufactured in an order of magnitude that is less than 10 mm in diameter, in particular less than 3 mm in diameter, with an axial length of less than 10 mm, the pump or the motor largely by wire erosion, possibly under Die-sinking erosion for the non-cylindrical shapes, such as kidney grooves (41k, 42k), is very limited in terms of production. Process for uniaxially fitting and assembling functional parts (20, 30, 50, 41, 42, 60) of a pump or a motor of the smallest size (micropump, micromotor), especially in the area under 10 mm in diameter, in order to be largely cylindrical a first and a second insert (41, 42) are pushed into a sleeve (60) on the end face in order to hold an inner rotor (20) and an outer rotor (30) with axially offset axes (101, 100) between them. Motor according to Claim 10 or 9, in which the outlet opening (42n) also has an axial direction, parallel to the axes (100, 101) of the sleeve and inner rotor (20).

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