EP4180665A1 - Internal gear pump with pressure pockets on the hollow wheel and/or on the housing - Google Patents

Abstract

Rotary pump comprising: a housing (1) with a pumping chamber (5), which the housing (1) surrounds and axially delimits at the end faces and which has an inlet (6) for the fluid on a low-pressure side of the rotary pump and an outlet (7) for has the fluid on a high-pressure side of the rotary pump, an inner rotor (4) which can be rotated in the delivery chamber (5), an outer rotor (3) which can be rotated in the delivery chamber (5) about a pump axis of rotation (R₃) and forms delivery cells with the inner rotor (4), and a peripheral bearing wall (2) formed by the housing (1) or arranged in the housing (1), which surrounds the outer rotor (3) and around the pump axis of rotation (R₃ ) rotatably supported in a radial sliding contact, the peripheral bearing wall (2) having a plurality of blind pockets (21, 22, 23, 24) radially open to the outer rotor (3) and/or the outer rotor (3) having a plurality of blind pockets (21, 22, 23, 24) radially open to the peripheral bearing wall (2). 21, 22, 23, 24) which are fluidically separated from one another in the area of sliding contact between the outer rotor (3) and the peripheral bearing wall (2).

Description

The invention relates to a rotary pump for conveying a fluid, in particular the rotary pump relates to an electrically driven rotary pump. The rotary pump is preferably an electric rotary pump for pumping oil to supply a machine unit. In particular, the rotary pump is an oil pump for a motor vehicle for supplying an engine and/or a transmission with oil, in particular lubricating oil. The rotary pump includes a housing with a pumping chamber that surrounds the housing and is axially delimited at the end faces. The pumping chamber has at least one inlet for the fluid on a low-pressure side of the rotary pump and an outlet for the fluid on the high-pressure side of the rotary pump.

A rotatable inner rotor is formed in the pumping chamber of the rotary pump, as is an outer rotor which is rotatable about a pump axis of rotation and forms pumping cells with the inner rotor. The pump axis of rotation of the inner rotor is eccentric to the pump axis of rotation of the outer rotor. A peripheral bearing wall formed by the housing or arranged in the housing surrounds the outer rotor radially on the outside and supports it rotatably in sliding contact.

In practice, rotary pumps with an outer rotor mounted radially on the outside have starting problems, especially after long periods of standstill, which are caused in particular by the friction of the outer peripheral surface of the outer rotor with the inner peripheral surface of the peripheral bearing wall. The adhesive and/or frictional forces between the outer peripheral surface of the inner rotor and the inner peripheral surface of the peripheral bearing wall can be so great that when the pump starts up, initially no or only very little fluid is pumped. This can too Damage to the pump and/or to the units that are to be supplied with the fluid that is pumped through the pump.

In addition to the starting problems, the fluid in the lubricating gap between the outer peripheral surface of the outer rotor and the inner peripheral surface of the peripheral bearing wall can produce viscous friction, particularly at high speeds, which has a negative effect on the efficiency of the rotary pump. Since the viscous friction results in particular from the adhesion of the fluid to the stationary inner peripheral surface of the peripheral bearing wall and the movable outer peripheral wall of the outer rotor and the resulting shearing of the fluid, the viscous frictional forces can increase with the speed of the pump, which means that the required drive power of the rotary pump is disproportionately high can increase to the speed.

Therefore, in conventional rotary pumps with an outer rotor mounted radially on the outside, both the outer peripheral surface of the outer rotor and the inner peripheral surface of the peripheral bearing wall are additionally machined in order to achieve a high surface quality and to minimize adhesive and/or frictional forces. Such processing steps require a high level of precision so that tolerances are maintained and the lubricating gap between the outer rotor and the peripheral bearing wall does not become too large. Such work steps are not only time-consuming, but above all expensive.

It is therefore an object of the invention to reduce the driving power of the rotary pump and to provide a rotary pump which can be manufactured at low cost.

This object is achieved by the rotary pump having the features of claim 1.

In order to achieve the object, the invention proposes a rotary pump for conveying a fluid, which comprises a housing with a conveying space. The pumping chamber is surrounded by the housing and axially delimited at the end faces and has an inlet for the fluid on a low-pressure side of the rotary pump and an outlet for the fluid on a high pressure side of the rotary pump. The housing can be designed in several pieces, in particular in two pieces. The housing preferably comprises at least one housing cover and one housing pot. The housing pot preferably delimits the conveying chamber radially on the outside and on an axial end face, while the housing cover axially delimits the conveying chamber on the end face of the conveying chamber facing away from the housing pot.

In the pumping chamber of the rotary pump, there is an inner rotor that can be rotated about an axis of rotation and an outer rotor that can be rotated about a pump axis of rotation and forms pumping cells with the inner rotor. The pump axis of rotation of the inner rotor is preferably eccentric to the pump axis of rotation of the outer rotor, i.e. the pump axis of rotation of the inner rotor and the pump axis of rotation of the outer rotor are offset. The eccentricity of the pump axis of rotation of the outer rotor and the pump axis of rotation of the inner rotor can be constant or variable during pump operation. In the case of a variable eccentricity of the two pump axes of rotation, this can be controlled, in particular regulated, for example as a function of the operating state of the rotary pump.

The inner rotor of the rotary pump is preferably driven via a drive means, in particular a drive shaft. The inner rotor can drive the outer rotor. In alternative versions, the outer rotor can also be driven by a drive means, in particular by a drive shaft. In this case, the outer rotor can drive the inner rotor. Both the inner rotor and the outer rotor can also be driven by one drive means.

The rotary pump is preferably designed as an electrically driven rotary pump. This means that drive means, for example a drive shaft, of the inner rotor and/or the outer rotor can be driven by an electric motor. In alternative designs, the inner rotor and/or the outer rotor can be driven by the unit to be supplied with fluid, in particular the engine of a motor vehicle.

The rotary pump is preferably designed as an internal gear pump, with the external rotor being formed by an internally toothed ring gear and the internal rotor being formed by an externally toothed gear wheel. The inner rotor preferably has at least one tooth less than the outer rotor. The outer rotor can have five teeth, for example, and the inner rotor can have four teeth, for example. The conveyor cells can be formed by meshing the teeth of the outer rotor with the teeth of the inner rotor. In particular, due to the eccentricity of the two pump axes of rotation, the size of the delivery cells changes in the circumferential direction of the outer rotor, in particular in the direction of rotation of the outer rotor. Internal gear pumps are well known to those skilled in the art, which is why their structure will not be discussed further at this point. In alternative versions, the rotary pump can also be formed by a pendulum slide pump, for example.

A peripheral bearing wall formed by or disposed within the housing surrounds and rotatably supports the outer rotor in sliding contact. The outer rotor can be supported by the peripheral bearing wall in radial sliding contact, in particular in circumferential sliding contact. The peripheral bearing wall can be formed by the housing, in particular the housing pot, or by a separate component which is arranged in the housing, in particular a housing ring. The peripheral bearing wall is preferably part of the housing, in particular of the housing pot, and surrounds the outer rotor radially on the outside. The peripheral bearing wall can be joined to an end wall of the housing or molded, for example cast or sintered, and together with the end wall form the housing pot.

The peripheral bearing wall has an inner peripheral surface which is preferably cylindrical, in particular circular-cylindrical. The outer rotor has an outer peripheral surface which is preferably cylindrical, in particular circular-cylindrical. The peripheral bearing wall, in particular the inner peripheral surface of the peripheral bearing wall, and the outer rotor, in particular the outer peripheral surface of the outer rotor, are preferably formed concentrically to one another.

The peripheral bearing wall preferably surrounds the outer rotor with a clearance such that the inner diameter of the peripheral bearing wall is larger than the outer diameter of the outer rotor. The inside diameter of the peripheral bearing wall can be at least 60 μm, in particular at least 70 μm, larger than the outside diameter of the outer rotor. The inside diameter of the peripheral bearing wall is preferably at most 110 μm, preferably at most 95 μm, larger than the outside diameter of the outer rotor. The clearance between the outer rotor and the peripheral bearing wall should not be too large in order to prevent fluid flow through the gap between the outer rotor and the peripheral bearing wall.

The peripheral bearing wall and/or the outer rotor preferably have a plurality of blind pockets that are radially open to the outer rotor or to the peripheral bearing wall. The peripheral bearing wall preferably has a plurality of blind pockets which are radially open towards the outer rotor. In alternative designs, the outer rotor can have a plurality of blind pockets that are radially open toward the peripheral bearing wall. The blind pockets interrupt the cylindrical, in particular circular-cylindrical, inner peripheral surface of the peripheral bearing wall and/or the cylindrical, in particular circular-cylindrical, outer peripheral surface of the outer rotor.

In this way, the outer rotor and the inner peripheral surface are not in contact with one another in the area of the blind pockets. In this way, the effort for machining the inner peripheral surface of the peripheral bearing wall and/or the effort for machining the outer peripheral surface of the outer rotor can be reduced and costs can be saved. Furthermore, fluid that is located in the gap between the outer rotor and the peripheral bearing wall due to unavoidable leakage and is carried along by the rotation of the outer rotor can flow off into the blind pockets. In this way, the viscous friction can be significantly reduced.

The blind pockets are preferably arranged in an asymmetrical distribution over the circumference of the outer rotor with respect to the circumferential direction. In particular, have at least two adjacent blind pockets on the circumference of the outer rotor with respect to the circumferential direction at a distance from each other, which compared to the other distances between the blind pockets is different. In particular, two adjacent blind pockets in each case delimit an arc length of the outer circumference of the outer rotor in the circumferential direction, it being possible for the individual arc lengths delimited by the blind pockets to be different or the same size. Preferably, at least two adjacent blind pockets delimit an arc length of the outer circumference of the outer rotor in the circumferential direction, which is different from the other arc lengths delimited by the blind pockets.

Preferably, at least one blind pocket, preferably each of the blind pockets, overlaps over more than 80% or in particular more than 90% of its circumferential extent either with the inlet only or with the outlet only. At least one of the blind pockets, in particular each of the blind pockets, preferably overlaps over its entire circumferential extent either only with the inlet or only with the outlet.

In preferred embodiments, the rotary pump comprises at least three or four blind pockets and/or a maximum of five or six blind pockets. The rotary pump preferably includes an even number of blind pockets, in particular four blind pockets. In preferred embodiments, the rotary pump comprises an even number of blind pockets, in particular four blind pockets, with a first half of the blind pockets, in particular two of the blind pockets, overlapping over more than 80% or more than 90% of their circumferential extent only with the inlet and a second half the blind pockets, in particular the other two blind pockets, only overlap with the outlet over more than 80% or more than 90% of their circumferential extent.

In preferred embodiments, the rotary pump has an even number of blind pockets, in particular four blind pockets, which are arranged mirror-symmetrically with respect to the inner diameter of the peripheral bearing wall and/or the outer diameter of the outer rotor. The rotary pump preferably comprises four blind pockets, with two of the blind pockets forming a pair of pockets and the two pairs of pockets relative to the inner diameter the peripheral bearing wall and/or the outer diameter of the outer rotor are mirror-symmetrical to one another.

In particular, the rotary pump comprises an even number of blind pockets, which can be combined into a first and a second half, the blind pockets of the first half overlapping over more than 80% or more than 90% of their circumferential extent only with the inlet and the blind pockets of the second Half over more than 80% or more than 90% of their circumferential extent overlap only with the outlet. The two halves can be mirror-symmetrical to one another with respect to the inner diameter of the peripheral bearing wall and/or the outer diameter of the outer rotor.

In particular, the rotary pump comprises four blind pockets, which can be combined into two pairs of pockets, with the blind pockets of the first pair of pockets overlapping over more than 80% or more than 90% of their circumferential extent only with the inlet and the blind pockets of the second pair of pockets over more than 80% or more than 90% of their circumferential extent overlaps only with the outlet. The two pairs of pockets can be mirror-symmetrical to each other with respect to the inner diameter of the peripheral bearing wall and/or the outer diameter of the outer rotor.

One of the blind pockets, in particular each of the blind pockets, preferably extends at least twice as far in the circumferential direction of the outer rotor, preferably at least three times as far as in the radial direction of the outer rotor. The axial extent of one of the blind pockets, in particular each blind pocket, can correspond from a first end of the pocket to a second end of the pocket at least 70%, preferably at least 80%, of the axial extent of the outer rotor from a first end face of the outer rotor to a second end face of the outer rotor.

One of the blind pockets, in particular each of the blind pockets, can be in the form of a depression, in particular in the form of a recess, in the peripheral bearing wall and/or be formed in the outer rotor, which extends in the axial direction from the second end face of the outer rotor in the direction of the first end face of the outer rotor. The bottom of the pocket, preferably the bottom of each blind pocket, may have a radius. The radius of the base of the individual pockets, in particular of each blind pocket, is preferably smaller than the radius of the outer circumference of the outer rotor and/or the inner circumference of the peripheral bearing wall.

In relation to the circumference of the outer rotor, the blind pockets together have an extent in the circumferential direction of the outer rotor which corresponds to at least 20%, in particular at least 25%, of the circumference of the outer rotor. I.e. preferably at least 20% of the outer circumference of the outer rotor, in particular at least 25% of the outer circumference of the outer rotor, is overlapped by the blind pockets. In relation to the circumference of the outer rotor, the blind pockets together have an extension in the circumferential direction of the outer rotor which corresponds to a maximum of 50%, in particular a maximum of 60%, of the circumference of the outer rotor. This means that preferably a maximum of 50% of the outer circumference of the outer rotor, in particular a maximum of 60% of the outer circumference of the outer rotor, is overlapped by the blind pockets.

In particular, all blind pockets in the circumferential direction of the outer rotor preferably extend over a total of more than 120°, in particular over 150°, of the outer circumference of the outer rotor and/or preferably all blind pockets in the circumferential direction of the outer rotor extend over a maximum of 210°, in particular over 180° at the most °, the outer circumference of the outer rotor. One of the blind pockets, in particular each of the blind pockets, preferably extends in the circumferential direction over an arc angle which is at least as large as the arc angle of a tooth gap of the outer rotor on the pitch circle of the outer rotor.

In relation to the diameter of the outer rotor, the blind pockets have a radial extent which preferably corresponds to a maximum of 10% of the outer diameter of the outer rotor, in particular a maximum of 8% of the outer diameter of the outer rotor.

The blind pockets are preferably fluidically separated from one another in the area of the sliding contact between the outer rotor and the peripheral bearing wall. The blind pockets are preferably fluidically separated from one another in the region of the sliding contact between the outer rotor and the peripheral bearing wall in every rotational position of the outer rotor. In this respect, the sliding contact can also be regarded as a sealing contact. When it is mentioned in the course of the application that the blind pockets are fluidically separated from one another, this means in particular that there is no fluid flow from one blind pocket to one of the other blind pockets. This does not include natural, in particular unavoidable, leaks caused by the rotation of the outer rotor. In particular, no fluid is deliberately fed, for example through a supply line, into the sliding contact between the peripheral bearing wall and the outer rotor.

In preferred embodiments, the outer rotor extends axially beyond at least one of the blind pockets, preferably axially beyond each of the blind pockets, in sliding contact with the peripheral bearing wall toward the first face of the outer rotor. This means that the extent of the outer rotor in the axial direction can be greater than the axial extent of one blind pocket, in particular can be greater than the axial extent of each pocket. Alternatively or additionally, the peripheral bearing wall may extend axially beyond at least one of the blind pockets, preferably axially beyond each of the blind pockets, in sliding contact with the outer rotor toward the first face of the outer rotor. This means that the extent of the peripheral bearing wall in the axial direction can be greater than the axial extent of one blind pocket, in particular can be greater than the axial extent of each pocket.

If the outer rotor and/or the peripheral bearing wall in sliding contact extend/extends axially in the direction of the first end face of the outer rotor beyond at least one of the blind pockets, preferably beyond each of the blind pockets, the blind pocket, in particular each blind pocket, ends in the region of those in sliding contact Outer peripheral surface of the outer rotor or the inner peripheral surface of the peripheral bearing wall located in sliding contact is bag-shaped. In this way, one blind pocket, in particular each of the blind pockets, can be separated from the other Blind pockets be fluidically separated, especially in the area of the first end face of the outer rotor.

The peripheral bearing wall preferably surrounds the outer rotor in sliding contact in the area of the first end face of the outer rotor. In particular, the outer peripheral surface of the outer rotor is in sliding contact with the inner peripheral surface of the peripheral bearing wall in the region of the first end face of the outer rotor over the entire outer circumference of the outer rotor or the entire inner circumference of the peripheral bearing wall.

The sliding contact between the outer peripheral surface of the outer rotor and the inner peripheral surface of the peripheral bearing wall in the area of the first end face of the outer rotor preferably extends over 360°, so that a radial sealing gap is formed between the outer peripheral surface of the outer rotor and the inner peripheral surface of the peripheral bearing wall in the area of the first end face of the outer rotor. The radial sealing gap extends in the axial direction of the outer rotor, preferably over at least 10%, in particular over at least 15%, of the axial dimension of the outer rotor from its first end face to its second end face.

The radial sealing gap between the peripheral bearing wall and the outer rotor is preferably interrupted in the area of the first end face of the outer rotor by a maximum of one, in particular by none of the blind pockets. The radial sealing gap preferably serves to prevent a fluid connection between the blind pockets in the area of the first end face of the outer rotor.

A blind pocket, preferably each of the blind pockets, preferably runs open axially on the second end face of the outer rotor on the peripheral bearing wall and/or on the outer rotor. i.e. one of the blind pockets, preferably each of the blind pockets, has a second end of the pocket in the area of the second end face of the outer rotor, which end is preferably open. The outer rotor and/or the peripheral bearing wall extends/extends in sliding contact towards the second End face of the outer rotor axially preferably not beyond at least one of the blind pockets, preferably each of the blind pockets.

The peripheral bearing wall and the outer rotor can fluidly separate the respective blind pocket, preferably each of the blind pockets, from the other blind pockets at the open end in sliding contact, in particular in radial sliding contact. In the area of the blind pockets, the outer peripheral surface of the outer rotor preferably has no contact with the inner peripheral surface of the peripheral bearing wall, while the outer peripheral surface of the outer rotor and the inner peripheral surface of the peripheral bearing wall have sliding contact, preferably sealing contact, in the area between the blind pockets.

The housing preferably includes a housing cover, which axially delimits the delivery chamber on the second end face of the outer rotor and bears against the peripheral bearing wall with an axial sealing contact. In particular, the housing cover can form an axial sealing gap with the peripheral bearing wall. The axial sealing contact between the housing cover and the peripheral bearing wall is preferably formed over the entire periphery of the peripheral bearing wall in the peripheral direction of the peripheral bearing wall. Preferably, the axial sealing contact between the peripheral bearing wall and the housing cover, in particular between the end face of the peripheral bearing wall formed in the area of the second end face of the outer rotor and the end face of the housing cover facing the peripheral bearing wall, extends over 360° of the outer circumference of the peripheral bearing wall in the area of the second end face of the outer rotor . In this way, the blind pockets can be fluidically separated from one another in the area of the second end face of the outer rotor. If the blind pockets have an open end in the area of the second end face of the outer rotor, the blind pockets are preferably fluidically separated from one another in the area of the second pocket end by the axial sealing contact, in particular by the axial sealing gap.

The housing cover can bear against the outer rotor with an axially sealing sliding contact. Particularly preferably, the second end face of the outer rotor and the Housing cover, in particular an end face of the housing cover facing the outer rotor, has an axial sealing gap. The housing cover is preferably in axial sliding contact, in particular in axial sealing contact, on the outer rotor. The axial sealing gap between the housing cover and the peripheral bearing wall can be smaller than the axial sealing gap between the housing cover and the outer rotor.

The axial sealing gap between the housing cover and the outer rotor is preferably formed over the entire circumference of the outer rotor in the circumferential direction of the outer rotor. The axial sealing gap between the second end face of the outer rotor and the housing cover, in particular between the second end face of the outer rotor and the end face of the housing cover facing the outer rotor, preferably extends over 360° of the outer circumference of the outer rotor in the area of the second end face of the outer rotor. In this way, the blind pockets can be fluidically separated from one another in the area of the second end face of the outer rotor. If the blind pockets have an open end in the area of the second end face of the outer rotor, the blind pockets are preferably fluidically separated from one another in the area of the second pocket end by the axial sealing gap.

The outer rotor can have a chamfer on its first end face along its outer peripheral edge. An edge break is preferably a removal of edge material, i. H. the peripheral outer edge of the outer rotor is preferably not formed with sharp edges on the first end face. The edge break can be rounded, i.e. have a radius. The edge break is preferably formed over the entire length of the peripheral outer edge. The edge fracture preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or at most 500 μm in the radial direction. The edge fracture preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or at most 500 μm in the axial direction.

The chamfer, in particular the rotor bevel, can be produced during the manufacture of the outer rotor, in particular during the primary shaping of the outer rotor. Preferably will the outer rotor is produced in a primary shaping process, for example by sintering or casting. In alternative embodiments, the broken edge, in particular the rotor bevel, can be formed subsequently by deburring the outer peripheral edge, for example by brushing, grinding or filing.

The outer rotor particularly preferably has a rotor chamfer on its first end face along its outer peripheral edge. A chamfer in the sense of the application is preferably understood to mean a broken edge in the form of a beveled, in particular flat, surface defined in terms of width and angle. The beveled surface is preferably curved exclusively in the circumferential direction of the outer rotor.

The beveled surface, in particular the rotor bevel, can preferably be formed at an angle of 45° to the axial direction of the outer rotor. In alternative designs, the beveled surface, in particular the rotor bevel, can also be formed at an angle of 60° to the axial direction of the outer rotor. The rotor bevel can be formed at any other angle greater than 0° and less than 90° to the axial direction of the outer rotor. The rotor bevel preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or at most 500 μm in the radial direction. The rotor bevel preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or at most 500 μm in the axial direction. In particular, the rotor bevel measures at least 300 μm in the radial and axial direction at an angle of 45° to the axial direction of the outer rotor.

The peripheral bearing wall may have an inner edge transition along its inner peripheral edge on the first face of the outer rotor, ie on the axial side of the first face of the outer rotor. An inner edge transition is preferably an overhang of material, ie the inner peripheral edge of the peripheral bearing wall is preferably not formed with sharp edges on the first end face of the outer rotor. The inner edge transition can be rounded, ie have a radius. Preferably, the inner edge transition is formed over the entire length of the peripheral inner edge. In particular, in the event that the peripheral bearing wall is formed in one piece with an end wall of the housing, the Inner edge transition formed along the inner edge between the end wall and the peripheral bearing wall.

More preferably, the peripheral bearing wall on the first face of the outer rotor has an inner edge burr along its inner peripheral edge. An inner edge burr in the sense of the application is preferably understood to mean an inner edge transition in the form of a beveled, in particular flat, surface defined in terms of width and angle. The beveled surface is preferably curved exclusively in the circumferential direction of the circumferential bearing wall.

The inner edge transition, in particular the inner edge burr, can be produced when the peripheral bearing wall is manufactured, in particular when the peripheral bearing wall is originally formed. The peripheral bearing wall is preferably produced as part of the housing pot in a primary shaping process, for example by sintering or casting. The inner edge transition, in particular the inner edge burr, is preferably formed in a subsequent manufacturing step during the post-processing of the inner peripheral surface of the peripheral bearing wall, for example by milling, grinding or honing.

The chamfered surface, in particular the inner edge burr, may preferably be formed at an angle of 45° to the axial direction of the outer rotor or the peripheral bearing wall. In alternative embodiments, the beveled surface, in particular the inner edge burr, can also be formed at an angle of 60° to the axial direction of the outer rotor or the peripheral bearing wall. The inner edge burr can be formed at any other angle greater than 0° and less than 90° to the axial direction of the outer rotor or the peripheral bearing wall. The inner edge burr preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or 500 μm in the radial direction. The inner edge burr preferably measures at least 200 μm or at least 300 μm and/or at most 400 μm or at most 500 μm in the axial direction. In particular, the inner edge burr is at least 300 µm in the radial and axial directions at an angle of 45° to the axial direction of the outer rotor.

In particularly preferred embodiments, the outer rotor has an edge break and the peripheral bearing wall has an inner edge blend, and the outer rotor edge break overlaps the inner edge blend of the peripheral bearing wall. This means that the inner edge transition is particularly preferably designed in accordance with the chamfer. The inner edge transition forms, so to speak, an imprint or a negative of the broken edge. The inner edge transition preferably has the same radius or angle as the edge break. If the inner edge transition is an inner edge burr, the chamfer is preferably designed in the form of a rotor bevel, the angle to the axial direction of the outer rotor and the extension in the axial direction of the inner edge burr being equal to the angle to the axial direction of the outer rotor and the extension in the axial direction of the rotor bevel are.

Particularly preferably, the edge break is a rotor chamfer that measures at least 300 µm in the radial direction and at least 300 µm in the axial direction at an angle of 45° to the axial direction of the outer rotor, and the inner edge transition is an inner edge burr that measures at least 300 µm in the radial direction and at least 300 µm in the axial direction Direction measures at least 300 microns at an angle of 45 ° to the axial direction of the outer rotor.

In preferred embodiments, the peripheral bearing wall on the second face of the outer rotor along its inner peripheral edge and/or the outer rotor on its second face along its outer peripheral edge has no edge break or only a small second edge break. In cases where the peripheral bearing wall on the second face of the outer rotor along its inner peripheral edge and/or the outer rotor on its second face along its outer peripheral edge does not have an edge break, the edge is along the inner peripheral edge of the peripheral bearing wall and/or along the outer peripheral edge of the outer rotor sharp-edged.

In cases where the peripheral bearing wall on the second face of the outer rotor along its peripheral inner edge and/or the outer rotor on its second face along its peripheral outer edge has no edge fracture or only a small second Have / has edge fracture, at least one of the blind pockets, preferably each of the blind pockets, end axially open on the second end face of the outer rotor on the peripheral bearing wall and / or on the outer rotor. In this case, the missing edge break or the small second edge break along the inner peripheral edge of the peripheral bearing wall and/or along the outer peripheral edge of the outer rotor ensures that the blind pockets in the area of the second end face of the outer rotor along the inner peripheral edge of the peripheral bearing wall and/or along the outer peripheral edge of the outer rotor have no fluidic connection, in particular in the form of a fluid flow. The small second edge break, if present, along the inner peripheral edge of the peripheral bearing wall and/or along the outer peripheral edge of the outer rotor is preferably so small that no fluid flow can form between the individual blind pockets.

A very small second edge breakage is understood in particular as deburring along the inner peripheral edge of the peripheral bearing wall and/or along the outer peripheral edge of the outer rotor, in particular deburring by brushing, filing or grinding. This means that if there is a small second edge break, then this is the result of a deburring measure, but not a bevel defined in terms of width and angle. This means the small second edge break, if any, is not a chamfer with a bevel dimensionally defined in width and angle. The small second chamfer preferably has a maximum extent of 100 μm in the axial direction. In particular, the small second edge break has a maximum extent of 100 μm in the radial direction.

The outer rotor can have a chamfer, in particular a rotor bevel, on its first end face along its outer peripheral edge, and a small second chamfer on its second end face along its outer peripheral edge, with the chamfer, in particular the rotor bevel, being at least three times as large in the axial direction, in particular four times as large large, is like the second edge break.

The peripheral bearing wall can have an inner edge transition, in particular an inner edge burr, along its inner peripheral edge on the first end face of the outer rotor, and a small chamfer along its inner peripheral edge on the second end face of the outer rotor, the inner edge transition, in particular the inner edge burr, being at least three times as large in the radial direction in particular four times as large as the chamfer of the outer peripheral edge of the outer rotor on its first end face.

Figur 1:

eine Draufsicht auf den Förderraum der Rotationspumpe,

Figur 2:

einen Schnitt in Axialrichtung der Rotationspumpe mit Förderglied,

Figur 3:

eine Detailansicht des Schnitts aus Figur 2,

Figur 4:

einen axialen Schnitt durch den Außenrotors,

Figur 5:

eine Detailansicht des Axialschnitts aus Figur 4,

Figur 6:

eine Draufsicht auf den Förderraum der Rotationspumpe ohne Förderglied,

Figur 7:

einen axialen Schnitt durch die Rotationspumpe ohne Förderglied und

Figur 8:

eine Detailansicht des Axialschnitts aus Figur 7.

The invention is explained below using an exemplary embodiment. Features disclosed in the exemplary embodiment advantageously develop the subject matter of the claims and the configurations explained above, but do not limit the invention. Show it:

Figure 1:

a plan view of the pumping chamber of the rotary pump,

Figure 2:

a section in the axial direction of the rotary pump with conveying member,

Figure 3:

a detailed view of the section figure 2 ,

Figure 4:

an axial section through the outer rotor,

Figure 5:

a detailed view of the axial section figure 4 ,

Figure 6:

a top view of the pumping chamber of the rotary pump without a pumping element,

Figure 7:

an axial section through the rotary pump without the conveying member and

Figure 8:

a detailed view of the axial section figure 7 .

All figures show a rotary pump and its components of an embodiment. The invention is not limited to the exemplary embodiment and can be designed in accordance with the preceding statements.

figure 1 shows a plan view of the pumping chamber of the rotary pump, while figure 2 a section through the rotary pump figure 1 in the axial direction of the rotary pump. figure 3 shows a detailed view of the figure 2 . The Figures 6-8 show the rotary pump of figure 1 , only without the conveyor link 3, 4.

The rotary pump comprises a housing 1 with a pumping chamber 5, which surrounds the housing 1 and is axially delimited at the end faces. As in particular in the figures 2 and 7 As can be seen, the housing 1 comprises a housing pot 11 and a housing cover 12. The housing cover 12 delimits the pumping space in the axial direction, while the housing pot 11 surrounds the pumping space in the radial direction and delimits it axially on the side facing away from the housing cover 12. The pumping chamber 5 has an inlet 6 for a fluid on a low-pressure side of the rotary pump and an outlet 7 for the fluid on the high-pressure side of the pump.

A conveying element is formed in the conveying chamber 5 and conveys the fluid from the low-pressure side of the rotary pump, in particular from the inlet 6 , to the high-pressure side of the rotary pump, in particular the outlet 7 . The rotary pump is designed as an internal gear pump or gerotor pump. The conveying member comprises an outer rotor 3 and an inner rotor 4, the outer rotor 3 being formed by an internally toothed ring gear and the inner rotor 4 by an externally toothed gear, and the teeth of the inner rotor 4 are meshed with the teeth of the outer rotor 3 by the rotation of the two rotors can reach. The inner rotor 4 preferably has one tooth less than the outer rotor 3. In the exemplary embodiment, the outer rotor 3 has five teeth and the inner rotor 4 has four teeth, the number of individual teeth being only an example and can vary.

Through the engagement of the inner rotor 4 with the outer rotor 3, the two rotors form delivery cells which can change their volume in the circumferential direction of the outer rotor 3 as the two rotors rotate. In the present embodiment, the inner rotor 4, as in figure 2 is disclosed, driven by a drive means, in particular a drive shaft. The inner rotor 4 is rotatably mounted about the pump axis of rotation R ₄ and drives the outer rotor 3, in particular through the engagement of the individual teeth with one another. The inner rotor 4 is preferably driven by an electric motor. In alternative versions, the inner rotor 4 can also be driven by the unit to be supplied, for example. Furthermore, in alternative embodiments, the outer rotor 3 can also be driven by means of a drive means, with the inner rotor 4 being driven via the outer rotor 3 .

The pump axis of rotation R ₄ of the inner rotor 4 is eccentric to the pump axis of rotation R ₃ of the outer rotor 3, ie the pump axis of rotation R ₄ of the inner rotor 4 and the pump axis of rotation R ₃ of the outer rotor 3 are offset. The eccentricity of the pump axis of rotation R ₃ of the outer rotor 3 and the pump axis of rotation R ₄ of the inner rotor 4 is constant in the present exemplary embodiment, but can also be variable in alternative embodiments. With a variable eccentricity of the two pump axes of rotation, this can be changed, in particular controlled, for example as a function of the operating state of the rotary pump.

The housing pot 11 forms a circumferential bearing wall 2, which surrounds the outer rotor 3 and is rotatably mounted in a sliding contact about the pump axis of rotation R ₃ . In alternative embodiments, the peripheral bearing wall 2 can also be formed, for example, by a separate ring inserted into the conveying chamber 5 . As for example in figure 2 shown, the peripheral bearing wall 2 is integrally formed with the housing pot 11, in particular an end wall of the housing pot 11, in particular in a primary forming process.

As in figure 1 As can be seen, the peripheral bearing wall 2 has a plurality of blind pockets 21, 22, 23, 24 which are radially open to the outer rotor 3 and which are fluidically separated from one another in the area of the sliding contact between the outer rotor 3 and the peripheral bearing wall 2. According to the exemplary embodiment, the rotary pump comprises four blind pockets 21 , 22 , 23 , 24 formed in the peripheral bearing wall 2 . In alternative implementations, the number of blind pockets can vary and is not intended to be limited to four blind pockets. The blind pockets are fluidically separated from each other in every rotational position of the outer rotor 3 . i.e. Irrespective of the angular position of the outer rotor 3, the blind pockets 21, 22, 23, 24 are fluidically separated from one another in the area of the radial sliding contact of the outer rotor 3 and the peripheral bearing wall 2.

In alternative embodiments, the blind pockets 21, 22, 23, 24 in the outer rotor 3 and in the direction of the peripheral bearing wall 2 are designed to be radially open. Also in the event that the blind pockets 21, 22, 23, 24 are formed in the outer rotor 3, the Blind pockets 21, 22, 23, 24 in the area of the radial sliding contact of the outer rotor 3 and the peripheral bearing wall 2 are fluidically separated from one another, regardless of the angular position of the outer rotor 3.

The peripheral bearing wall 2 surrounds the outer rotor 3 in the area of a first end face 31 of the outer rotor 3 in a radial sliding contact. In particular, the outer peripheral surface of the outer rotor 3 is in sliding contact with the inner peripheral surface of the peripheral bearing wall 2 in the region of the first end face 31 of the outer rotor 3 over the entire outer circumference of the outer rotor 3 or the entire inner circumference of the peripheral bearing wall 2 in order to form a radial sealing gap. The radial sealing gap extends in the axial direction of the outer rotor 3 over at least 10%, in particular over at least 15%, of the axial dimension of the outer rotor 3 from its first end face 31 to its second end face 32.

As in figure 1 and figure 6 As can be seen, the blind pockets 21, 22, 23, 24 are arranged in an asymmetrical distribution over the circumference of the outer rotor 3 with respect to the circumferential direction. In particular, the blind pockets 22 and 23 are at a distance from one another over the circumference of the outer rotor 3 in relation to the circumferential direction, which is greater than the other distances between the individual blind pockets. For example, the distance between blind pocket 23 and blind pocket 24 is smaller than the distance between blind pockets 22 and 23.

As in particular from the figure 6 As can be seen, the blind pockets 23 and 24 in the circumferential direction of the outer rotor 3 or in the circumferential direction of the circumferential bearing wall 2 can only overlap with the outlet 7 over more than 90% of their circumferential extent. In particular, the blind pockets 23 and 24 in the circumferential direction of the circumferential bearing wall 2 completely overlap with the outlet 7. Furthermore, the blind pockets 21 and 22 in the circumferential direction of the outer rotor 3 or in the circumferential direction of the circumferential bearing wall 2 can only be connected to the inlet 6 over more than 90% of their circumferential extent overlap. In particular, the blind pockets 21 and 22 completely overlap the inlet 6 in the circumferential direction of the circumferential bearing wall 2.

As in the figures 2 and 6 disclosed, the rotary pump has four blind pockets 21, 22, 23, 24, which are arranged mirror-symmetrically with respect to the inner diameter d of the peripheral bearing wall 2 and/or the outer diameter D of the outer rotor 3. The blind pockets 21 and 22 form a first pair of pockets and the blind pockets 23 and 24 form a second pair of pockets, with the two pairs of pockets being mirror-symmetrical to one another with respect to the inner diameter d of the peripheral bearing wall 2 and/or the outer diameter D of the outer rotor 3. The axis of symmetry or the inner diameter d of the peripheral bearing wall 2 and/or the outer diameter D of the outer rotor 3 are in figure 6 shown as a dashed double arrow. The blind pockets 21, 22 of the first pair of pockets overlap with more than 80% or more than 90% of their circumferential extent only with the inlet 6 and the blind pockets 23, 24 of the second pair of pockets overlap with more than 80% or more than 90% of their circumferential extent only with outlet 7.

The blind pockets 21, 22, 23, 24 preferably extend in the circumferential direction of the outer rotor 3 at least twice as far, preferably at least three times as far as in the radial direction of the outer rotor 3. As in particular based on FIG Figures 3 and 8th As can be seen from the example of blind pocket 24, the axial extent of blind pockets 21, 22, 23, 24 from a first pocket end 24a to a second pocket end 24b can be at least 70%, preferably at least 80%, of the axial extent of outer rotor 3 from a first End face 31 correspond to a second end face 32 .

In relation to the circumference of the outer rotor 3, the blind pockets 21, 22, 23, 24 together have an extension in the circumferential direction of the outer rotor 3 which corresponds to at least 20%, in particular at least 25%, of the circumference of the outer rotor 3. This means that at least 20% of the outer circumference of the outer rotor 3, in particular at least 25% of the outer circumference of the outer rotor 3, are preferably overlapped by the blind pockets 21, 22, 23, 24.

In relation to the outer diameter D of the outer rotor 3, the blind pockets 21, 22, 23, 24 have a radial extent which preferably corresponds to a maximum of 10% of the outer diameter D of the outer rotor 3, in particular a maximum of 8% of the outer diameter D of the outer rotor 3.

How in particular based on the Figures 3 and 8th as can be seen from the blind pocket 24, the outer rotor 3 extends in sliding contact in the direction of its first end face 31 axially beyond the blind pocket 24. Preferably, the outer rotor 3 extends in sliding contact towards its first face 31 axially beyond each of the blind pockets 21, 22, 23, 24. According to the exemplary embodiment, the outer rotor 3 extends further in the axial direction than the blind pockets 21, 22, 23, 24.

The peripheral bearing wall 2 also extends in sliding contact in the direction of the first end face 31 of the outer rotor 3 axially beyond the blind pocket 24 . Preferably, the peripheral bearing wall 2 extends axially beyond each of the blind pockets 21, 22, 23, 24 in sliding contact towards the first end face 31 of the outer rotor 3. As in particular in figure 3 can be seen, the peripheral bearing wall 2 and the outer rotor 3 have the same axial extent. The blind pocket 24, however, has an axial extent that is smaller than the axial extent of the peripheral bearing wall 2 and the outer rotor 3.

Due to the fact that the outer rotor 3 and the peripheral bearing wall 2 in sliding contact extend axially beyond the blind pockets 21, 22, 23, 24 in the direction of a first end face 31 of the outer rotor 3, the blind pockets 21, 22, 23, 24 end in the area of the im Sliding contact located outer peripheral surface of the outer rotor 3 and located in sliding contact inner peripheral surface of the peripheral bearing wall 2 bag-shaped. Furthermore, the outer rotor 3 and the peripheral bearing wall 2 form a radial sealing gap in the area of the first end face 31 of the outer rotor 3 . The radial sealing gap is not broken through by any of the blind pockets 21, 22, 23, 24. In this way, the blind pockets 21, 22, 23, 24 are fluidically separated from one another in the region of the first end face 31 of the outer rotor 3.

In the area of the second end face 32 of the outer rotor 3, the blind pocket 24, preferably each of the blind pockets 21, 22, 23, 24, runs axially open on the peripheral bearing wall 2. i.e. The blind pocket 24, preferably each of the blind pockets 21, 22, 23, 24, has a second pocket end 24b in the region of the second end face 32 of the outer rotor 3, which end is open.

The outer rotor 3 and the peripheral bearing wall 2 do not extend axially beyond the blind pocket 24, preferably each of the blind pockets 21, 22, 23, 24, in sliding contact towards the second end face 32 of the outer rotor 3. The peripheral bearing wall 2 and the outer rotor 3 fluidly separate the blind pockets 21, 22, 23, 24 at the open end 24b in sliding contact between the individual blind pockets 21, 22, 23, 24 with one another.

Furthermore, the housing cover 12 , which axially delimits the pumping chamber 5 on the second end face 32 of the outer rotor 3 , bears against the peripheral bearing wall 2 with an axial sealing contact and forms an axial sealing gap with the peripheral bearing wall 2 . The housing cover 12 is in axial sliding contact with the outer rotor 3 . In particular, the second end face 32 of the outer rotor 3 and the housing cover 12 have an axial sealing gap. The housing cover 12 is in axial sliding contact, in particular an axial sealing contact, on the outer rotor 3 . The axial sealing gap between the housing cover 12 and the peripheral bearing wall 2 is smaller than the axial sealing gap between the housing cover 12 and the outer rotor 3.

The axial sealing gap between the housing cover 12 and the peripheral bearing wall 2 is formed in the peripheral direction of the outer rotor 3 over the entire circumference of the peripheral bearing wall 2 . In this way, the blind pockets 21 , 22 , 23 , 24 are fluidically separated from one another in the area of the second end face 32 of the outer rotor 3 by the peripheral bearing wall 2 and the housing cover 12 .

The axial sealing gap between the housing cover 12 and the outer rotor 3 is formed over the entire circumference of the outer rotor 3 in the circumferential direction of the outer rotor 3 . The axial sealing gap extends between the second end face 32 of the Outer rotor 3 and the housing cover 12. In this way, the blind pockets 21, 22, 23, 24 are fluidically separated from one another in the area of the second end face 32 of the outer rotor 3. In particular, since the blind pockets 21, 22, 23, 24 have an open pocket end 24b in the area of the second end face 32 of the outer rotor 3, the blind pockets 21, 22, 23, 24 are fluidically separated from one another in the area of the second pocket end 24b by the axial sealing gap . In particular, the blind pockets 21, 22, 23, 24 are fluidically separated from one another by the axial sealing gap between the housing cover 12 and the peripheral bearing wall 2 and the axial sealing gap between the housing cover 12 and the outer rotor 3 in the area of the second end face 32 of the outer rotor 3.

Like those in particular Figures 4 and 5 show, the outer rotor 3 has a chamfer 31a on its first end face 31 along its peripheral outer edge. As in particular from the figure 5 shows, the broken edge 31a according to the present exemplary embodiment is designed in the form of a rotor bevel. The rotor bevel preferably has an angle of 45° and extends at least 300 μm in the radial and axial direction. In alternative embodiments, the rotor bevel can also have a different angle, for example an angle of 60°. In particular, the outer rotor 3 has no sharp-edged transition between the first end face 31 and the outer peripheral surface on its first end face 31 along its peripheral outer edge.

As in particular in figure 8 disclosed, the peripheral bearing wall 2 on the first end face 32 of the outer rotor 3, ie on the axial side of the first end face 31 of the outer rotor 3, has an inner edge transition 2a along its inner peripheral edge. The inner edge transition 2a can be rounded, ie have a radius. According to the embodiment, the inner edge transition 2a is formed in the form of an inner edge burr over the entire length of the peripheral inner edge. The peripheral bearing wall 2 is formed in one piece with the end wall of the housing 1, in particular the housing pot 11, facing the first end face 31 of the outer rotor 3, and the inner edge transition 2a is formed along the inner edge between the end wall and the peripheral bearing wall 2.

The inner edge transition is preferably an inner edge burr which measures at least 300 μm in the radial and axial direction. In this case, the inner edge burr has an angle of 45° to the axial direction of the outer rotor 3 .

The inner edge burr and the rotor chamfer 31a overlap each other when the outer rotor 3 is installed. That is, the inner edge burr is dimensionally and angle-matched to the rotor land, and/or the rotor land 31a is dimensionally and angle-matched to the inner edge burr. The outer rotor 3 preferably forms a sliding contact with the peripheral bearing wall 2 in the region of the rotor bevel 31a.

The outer rotor 3 has no chamfer on its second end face 32 or only a small second chamfer 32a. The small second chamfer 32a extends a maximum of 100 μm in the radial and axial direction. The outer peripheral edge 32a of the outer rotor 3 is preferably formed with sharp edges on its second end face 32 .

In the event that the outer rotor 3 has a second small chamfer 32a on its outer peripheral edge of the second end face 32, this corresponds at most to one third of the first chamfer 31a.

Reference List

1

Housing

11

housing pot

12

housing cover

2

perimeter bearing wall

2a

inside edge transition

21

blind pocket

22

blind pocket

23

blind pocket

24

blind pocket

24a

first pocket end

24b

second pocket end

3

outer rotor

31

first face

31a

first edge break

32

second face

32a

second edge break

4

inner rotor

5

conveyor room

6

inlet

7

outlet

i.e

inner diameter

D

outer diameter

R3

pump axis of rotation

R4

Pump axis of rotation inner rotor

Claims (16)

Rotary pump for delivering a fluid, the rotary pump comprising: 1.1 a housing (1) with a pumping chamber (5), which surrounds the housing (1) and delimits it axially at the end faces and which has an inlet (6) for the fluid on a low-pressure side of the rotary pump and an outlet (7) for the fluid on a high-pressure side of the rotary pump, 1.2 an inner rotor (4) that can be rotated in the conveying chamber (5), 1.3 an outer rotor (3) which can be rotated about a pump axis of rotation (R ₃ ) in the delivery chamber (5) and forms delivery cells with the inner rotor (4), and 1.4 a peripheral bearing wall (2) formed by the housing (1) or arranged in the housing (1), which surrounds the outer rotor (3) and is mounted in radial sliding contact so that it can rotate about the pump axis of rotation (R ₃ ), 1.5 wherein the peripheral bearing wall (2) has several blind pockets (21, 22, 23, 24) radially open towards the outer rotor (3) and/or the outer rotor (3) has several blind pockets (21, 22, 23, 24) radially open towards the circumferential bearing wall (2). ) which are fluidically separated from one another in the area of sliding contact between the outer rotor (3) and the peripheral bearing wall (2). Rotary pump according to the preceding claim, in which the outer rotor (3) and/or the peripheral bearing wall (2) slide in sliding contact towards a first end face (31) of the outer rotor (3) axially via at least one of the blind pockets (21, 22, 23, 24 ), preferably each of the blind pockets (21, 22, 23, 24), so that the respective pocket (21, 22, 23, 24) in the area of the outer peripheral surface of the outer rotor (3) or the the inner peripheral surface of the peripheral bearing wall (2) in sliding contact ends in a sack shape at a first pocket end (24a) and is thereby fluidically separated from the one or more blind pockets on the first end face (31) of the outer rotor (3). Rotary pump according to one of the preceding claims, wherein at least one of the blind pockets (21, 22, 23, 24), preferably each of the blind pockets (21, 22, 23, 24), on a second end face (32) of the outer rotor (3) on the Circumferential bearing wall (2) and / or on the outer rotor (3) expires open axially. Rotary pump according to the preceding claim, wherein the peripheral bearing wall (2) and/or the outer rotor (3) has the respective blind pocket (21, 22, 23, 24), preferably each blind pocket (21, 22, 23, 24), at the open end fluidically separate/separates in sliding contact from the one or more blind pockets. Rotary pump according to one of the two immediately preceding claims, wherein the housing (1) has a housing cover (12) which axially delimits the delivery chamber (5) on the second end face (32) of the outer rotor (3), and wherein the housing cover (12) on the peripheral bearing wall (2) with axial sealing contact and/or the housing cover (12) on the outer rotor (3) with an axially sealing sliding contact. Rotary pump according to one of the preceding claims, wherein the housing (1) has a housing cover (12) which axially delimits the delivery chamber (5) on the second end face (32) of the outer rotor (3) and with the peripheral bearing wall (2) and the outer rotor (3) forms an axial sealing gap, and wherein the axial sealing gap between the housing cover (12) and the peripheral bearing wall (2) is smaller than the axial sealing gap between the housing cover (12) and the outer rotor (3). Rotary pump according to one of Claims 1 to 5, in which the outer rotor (3) has a chamfer (31a), in particular a rotor chamfer, on its first end face (31) along its peripheral outer edge, and/or the peripheral bearing wall (2) on the first end face (31a) of the outer rotor (3) along its peripheral inner edge has or has an inner edge transition (2a), in particular an inner edge burr. A rotary pump according to the preceding claim, wherein the edge break (31a) on the outer rotor (3) overlaps with the inner edge transition (2) on the peripheral bearing wall (2). Rotary pump according to one of the preceding claims, wherein the peripheral bearing wall (2) on the second end face (32) of the outer rotor (3) along its inner peripheral edge and/or the outer rotor (3) on its second end face (32) along its outer peripheral edge has no edge break or only have/has a small second edge break (32a). Rotary pump according to one of the three preceding claims, wherein the outer rotor (3) has a second chamfer (32a) on its second end face (32) along its peripheral outer edge and the first chamfer (31a) in the radial and/or axial direction is at least three times as large or is four times as large as the second edge break (32a). Rotary pump according to one of the four preceding claims, wherein the outer rotor (3) has a chamfer (31a), in particular a rotor chamfer, on its first end face (31) along its peripheral outer edge, and the chamfer (31a) in the radial direction is at least 200 µm or at least 300 µm and/or at most 400 µm or 500 µm, and/or wherein the broken edge (31a) measures at least 200 µm or at least 300 µm and/or at most 400 µm or at most 500 µm in the axial direction. Rotary pump according to one of the preceding claims, in which the blind pockets (21, 22, 23, 24) are arranged over the circumference of the outer rotor (3) in asymmetrical distribution with respect to the circumferential direction. Rotary pump according to one of the preceding claims, wherein the respective blind pocket (21, 22, 23, 24) over more than 80% or more than 90% of its circumferential extent, preferably over the entire circumferential extent, either only with the inlet (6) or only with the outlet (7) overlaps. Rotary pump according to one of the preceding claims, wherein the rotary pump comprises four blind pockets (21, 22, 23, 24) and the blind pockets (21, 22, 23, 24) with respect to an inner diameter (d) of the peripheral bearing wall (2) and/or an outer diameter (D) of the outer rotor (3) are arranged mirror-symmetrically. Rotary pump according to one of the preceding claims, wherein the blind pockets (21, 22, 23, 24) extend in the circumferential direction of the outer rotor (3) at least twice as far, preferably at least three times as far as in the radial direction of the outer rotor (3). Rotary pump according to one of the preceding claims, wherein the axial extension of the blind pockets (21, 22, 23, 24) from the first pocket end (24a) to the second pocket end (24b) is at least 70%, preferably at least 80%, of the axial extension of the Outer rotor (3) from the first end face (31) to the second end face (32).

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