Pressure bladder on hollow wheel

Abstract

A rotary pump comprises a housing having a delivery space (5), the housing surrounding the delivery space (5) and axially delimiting the delivery space (5) on the end side; an inner rotor (4) rotatable in the delivery space (5); an outer rotor (3) rotatable in the delivery space (5) about a pump rotation axis (R3) and forming a delivery unit with the inner rotor (4); and a circumferential support wall (2) rotatably mounted about the pump rotation axis in radial sliding contact and surrounding the outer rotor; wherein the circumferential support wall comprises a plurality of blind cavities (21, 22, 23, 24) radially opening toward the outer rotor, and / or the outer rotor comprises a plurality of blind cavities (21, 22, 23, 24) radially opening toward the circumferential support wall.

Description

Technical Field

[0001] The present invention relates to a rotary pump for conveying a fluid; in particular, the rotary pump is an electrically driven rotary pump. The rotary pump is preferably an electric rotary pump for conveying oil for supplying machine components. The rotary pump is particularly an oil pump for use in motor vehicles, for conveying oil, in particular lubricating oil, to the engine and / or transmission. The rotary pump comprises a housing having a conveying space, which encloses the conveying space and axially delimits the conveying space at its end faces. The conveying space includes at least one inlet for fluid on the low-pressure side of the rotary pump and an outlet for fluid on the high-pressure side of the rotary pump. Background Art

[0002] A rotatable inner rotor is formed in the delivery chamber of the rotary pump, as is an outer rotor. The outer rotor is rotatable about the pump rotation axis and, together with the inner rotor, forms a delivery unit. The pump rotation axis of the inner rotor is eccentrically arranged relative to the pump rotation axis of the outer rotor. A circumferential support wall formed by or arranged in the housing radially surrounds the outer rotor and rotatably supports it in sliding contact.

[0003] In practice, rotary pumps with an outer rotor mounted radially outwardly experience startup problems, particularly after prolonged periods of standstill. This is caused, inter alia, by friction between the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall. Adhesion and / or friction between the outer circumferential surface of the inner rotor and the inner circumferential surface of the circumferential support wall can be so great that, when the pump is started, initially no fluid is delivered, or only very little fluid is delivered. This can damage the pump and / or components to which the fluid delivered by the pump is supplied.

[0004] In addition to starting issues, the fluid in the lubrication gap between the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall generates viscous friction, which negatively impacts the efficiency of the rotary pump, particularly at high rotational speeds. Because viscous friction is caused, inter alia, by the fluid adhering to the stationary inner circumferential surface of the circumferential support wall and the moving outer circumferential wall of the outer rotor, and by the resulting shearing of the fluid, the viscous friction can increase with the rotational speed of the pump, thereby increasing the required drive output of the rotary pump disproportionately with respect to the rotational speed.

[0005] In conventional rotary pumps that include an outer rotor mounted radially outward, both the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall are additionally machined to achieve high surface quality and minimize adhesion and / or friction. This machining step requires high precision to adhere to tolerances and prevent the lubrication gap between the outer rotor and the circumferential support wall from becoming too large. This process step is not only time-consuming but also extremely expensive. Summary of the Invention

[0006] Therefore, an object of the present invention is to reduce the drive output of a rotary pump and to provide a rotary pump that can be manufactured at low cost.

[0007] This object is achieved by a rotary pump comprising the features according to claim 1 .

[0008] To achieve this objective, the present invention provides a rotary pump for conveying a fluid, the pump comprising a housing having a delivery chamber. The delivery chamber is surrounded and axially delimited by the housing at its end faces and comprises an inlet for the fluid on the low-pressure side of the rotary pump and an outlet for the fluid on the high-pressure side of the rotary pump. The housing can be constructed in multiple pieces, in particular in two pieces. The housing preferably comprises at least a housing cover and a housing cup. Preferably, the housing cup delimits the delivery chamber on its radially outer side and on one axial end face, while the housing cover delimits the delivery chamber axially on the end face of the delivery chamber facing away from the housing cup.

[0009] An inner rotor rotatable about a rotation axis and an outer rotor rotatable about the pump rotation axis and forming a delivery unit with the inner rotor are formed in the delivery space of the rotary pump. The pump rotation axis of the inner rotor is preferably eccentric relative to the pump rotation axis of the outer rotor, i.e., the pump rotation axis of the inner rotor and the pump rotation axis of the outer rotor are offset. During pump operation, the eccentricity between the pump rotation axis of the outer rotor and the pump rotation axis of the inner rotor can be constant or variable. If the eccentricity between the two pump rotation axes is variable, the eccentricity can be controlled, and in particular adjusted, depending on, for example, the operating state of the rotary pump.

[0010] Preferably, the inner rotor of the rotary pump is driven by a drive device, in particular a drive shaft, wherein the inner rotor can drive the outer rotor. In an alternative embodiment, the outer rotor can also be driven by a drive device, in particular a drive shaft. The outer rotor can then drive the inner rotor. Alternatively, both the inner rotor and the outer rotor can be driven by the drive device.

[0011] The rotary pump is preferably an electrically driven rotary pump. This means that the drive of the inner and / or outer rotor, for example a drive shaft, can be driven by an electric motor. In an alternative embodiment, the inner and / or outer rotor can be driven by the component to be supplied with fluid, in particular the engine of a motor vehicle.

[0012] The rotary pump is preferably implemented as an internal gear pump, wherein the outer rotor consists of an inner ring gear and the inner rotor consists of an outer gear. The inner rotor preferably includes at least one tooth less than the outer rotor. The outer rotor may include, for example, five teeth, and the inner rotor may include, for example, four teeth. The delivery unit can be formed, for example, by interlocking the teeth of the outer rotor with the teeth of the inner rotor. In particular, due to the eccentricity between the two pump rotation axes, the size of the delivery unit varies in the circumferential direction of the outer rotor, especially in the direction of rotation of the outer rotor. Internal gear pumps are sufficiently well known to those skilled in the art, so their structure will not be discussed in more detail here. In an alternative embodiment, the rotary pump can also be formed, for example, by a pendulum-slider pump.

[0013] A circumferential support wall formed by or arranged in the housing surrounds the outer rotor and rotatably supports it in sliding contact. The outer rotor can be mounted by the circumferential support wall in radial sliding contact, in particular circumferential sliding contact. The circumferential support wall can be formed by the housing, in particular the housing cup, or by a separate component arranged in the housing, in particular a housing ring. The circumferential support wall is preferably part of the housing, in particular the housing cover, and surrounds the outer rotor radially on the outside. The circumferential support wall can be connected to the end wall of the housing or integrally molded, for example cast or sintered, and together with the end wall can form the housing cup.

[0014] The circumferential support wall includes an inner circumferential surface that is preferably cylindrical, particularly circular-cylindrical. The outer rotor includes an outer circumferential surface that is preferably cylindrical, particularly circular-cylindrical. The circumferential support wall and the outer rotor, particularly the inner circumferential surface of the circumferential support wall and the outer circumferential surface of the outer rotor, are preferably formed concentrically relative to each other.

[0015] The circumferential support wall preferably surrounds the outer rotor with a gap such that the inner diameter of the circumferential support wall is larger than the outer diameter of the outer rotor. The inner diameter of the circumferential support wall may be at least 60 μm larger than the outer diameter of the outer rotor, and in particular at least 70 μm larger. The inner diameter of the circumferential support wall is preferably at most 110 μm larger than the outer diameter of the outer rotor, and preferably at most 95 μm larger. The gap between the outer rotor and the circumferential support wall should not be too large to prevent fluid from flowing through the gap between the outer rotor and the circumferential support wall.

[0016] The circumferential support wall and / or the outer rotor preferably include a plurality of blind pockets that are radially open toward the outer rotor and / or the circumferential support wall. The circumferential support wall preferably includes a plurality of blind pockets that are radially open toward the outer rotor. In an alternative embodiment, the outer rotor may include a plurality of blind pockets that are radially open toward the circumferential support wall. The blind pockets interrupt the cylindrical, in particular circular-cylindrical, inner circumference of the circumferential support wall and / or the cylindrical, in particular circular-cylindrical, outer circumference of the outer rotor.

[0017] In this way, the outer rotor and the inner circumferential surface do not contact each other in the area of the blind pocket. This reduces the effort and / or expense of machining the inner circumferential surface of the circumferential support wall and / or the effort and / or expense of machining the outer circumferential surface of the outer rotor, saving costs. Fluid that inevitably leaks into the gap between the outer rotor and the circumferential support wall and is controlled by the rotation of the outer rotor can also flow into the blind pocket. This significantly reduces viscous friction.

[0018] Preferably, the blind cavities are asymmetrically distributed around the circumference of the outer rotor relative to the circumferential direction. Specifically, at least two adjacent blind cavities are spaced apart from each other along the circumference of the outer rotor relative to the circumferential direction, and this distance is different from other distances between the blind cavities. Specifically, every two adjacent blind cavities define an arc length of the outer circumference of the outer rotor in the circumferential direction, wherein the arc lengths defined by the blind cavities may be different or the same in size. Preferably, at least two adjacent blind cavities define an arc length of the outer circumference of the outer rotor in the circumferential direction, and this arc length is different from other arc lengths defined by the blind cavities.

[0019] At least one blind cavity, preferably each blind cavity, preferably overlaps only with the inlet or only with the outlet for more than 80%, or in particular more than 90%, of its circumference. At least one blind cavity, preferably each blind cavity, preferably overlaps only with the inlet or only with the outlet for more than 80%, or in particular more than 90%, of its circumference.

[0020] In a preferred embodiment, the rotary pump comprises at least three or four blind cavities and / or at most five or six blind cavities. The rotary pump preferably comprises an even number of blind cavities, in particular four blind cavities. In a preferred embodiment, the rotary pump comprises an even number of blind cavities, in particular four blind cavities, wherein in each case the first half of the blind cavities, in particular two of the blind cavities, overlaps with the inlet only by more than 80% or 90% of their circumferential extension, respectively, and the second half of the blind cavities, in particular the other two blind cavities, overlaps with the outlet only by more than 80% or 90% of their circumferential extension.

[0021] In a preferred embodiment, the rotary pump comprises an even number of blind cavities, in particular four blind cavities, which are arranged mirror-symmetrically with respect to the inner diameter of the circumferential support wall and / or the outer diameter of the outer rotor. The rotary pump preferably comprises four blind cavities, wherein two blind cavities form a pair of cavities, and the two pairs of cavities are formed mirror-symmetrically with respect to each other with respect to the inner diameter of the circumferential support wall and / or the outer diameter of the outer rotor.

[0022] In particular, the rotary pump comprises an even number of blind cavities, which can be grouped into a first and a second half, wherein the blind cavities of the first half overlap with the inlet only for more than 80% or 90% of their circumferential extension, and the blind cavities of the second half overlap with the outlet only for more than 80% or 90% of their circumferential extension. The two halves can be formed mirror-symmetrically with respect to one another with respect to the inner diameter of the circumferential support wall and / or the outer diameter of the outer rotor.

[0023] In particular, the rotary pump comprises four blind cavities, which can be grouped into two pairs of blind cavities, wherein the blind cavities of a first pair of cavities overlap with the inlet only for more than 80% or 90% of their circumferential extension, and the blind cavities of a second pair of cavities overlap with the outlet only for more than 80% or 90% of their circumferential extension. The two pairs of cavities can be formed mirror-symmetrically with respect to one another with respect to the inner diameter of the circumferential support wall and / or the outer diameter of the outer rotor.

[0024] Preferably, one of the blind cavities, in particular each of the blind cavities, extends in the circumferential direction of the outer rotor for a length that is at least twice, preferably at least three times, the radial length of the outer rotor. The axial extent of one of the blind cavities, in particular each of the blind cavities, from the first end to the second end may correspond to at least 70%, preferably at least 80%, of the axial extent of the outer rotor from the first end side to the second end side of the outer rotor.

[0025] One of the blind pockets, in particular each of the blind pockets, can be formed as a recess, in particular a cavity, in the circumferential support wall and / or in the outer rotor, extending axially from the second end side of the outer rotor to the first end side of the outer rotor. The bottom of the pocket, in particular the bottom of each blind pocket, can have a radius. The radius of the bottom of each recess, in particular the radius of each blind pocket, is preferably smaller than the radius of the outer circumference of the outer rotor and / or the radius of the inner circumference of the circumferential support wall.

[0026] Relative to the circumference of the outer rotor, the blind cavities together have an extension in the circumferential direction of the outer rotor that corresponds to at least 20%, in particular at least 25%, of the circumference of the outer rotor, i.e., the blind cavities preferably overlap the outer circumference of the outer rotor by at least 20%, in particular at least 25% of the outer circumference of the outer rotor. Relative to the circumference of the outer rotor, the blind cavities together have an extension in the circumferential direction of the outer rotor that corresponds to at most 50%, in particular at most 60% of the circumference of the outer rotor, i.e., the blind cavities preferably overlap the outer circumference of the outer rotor by at most 50%, in particular at most 60% of the outer circumference of the outer rotor.

[0027] In particular, all the blind pockets preferably extend together in the circumferential direction of the outer rotor over a total of 120°, in particular over 150°, of the outer circumference of the outer rotor, and / or all the blind pockets preferably extend together in the circumferential direction of the outer rotor over a total of at most 210°, in particular at most 180°, of 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 that is at least as great as the arc angle of the tooth gap of the outer rotor on the pitch circle of the outer rotor.

[0028] Relative to the diameter of the outer rotor, the blind pockets have a radial extension which preferably corresponds to at most 10% of the outer diameter of the outer rotor, in particular at most 8% of the outer diameter of the outer rotor.

[0029] Preferably, the blind cavities are fluidically separated from one another in the sliding contact area between the outer rotor and the circumferential support wall. Preferably, in every rotational position of the outer rotor, the blind cavities are fluidically separated from one another in the sliding contact area between the outer rotor and the circumferential support wall. To this extent, the sliding contact can also be considered a sealing contact. In application, when the blind cavities are fluidically separated from one another, this particularly means that no fluid flows between one blind cavity and one of the other blind cavities. This does not include natural, in particular unavoidable, leakage caused by the rotation of the outer rotor. Thus, in particular, no fluid is intentionally fed, for example via a supply line, into the sliding contact between the circumferential support wall and the outer rotor.

[0030] In a preferred embodiment, the outer rotor, while in sliding contact with the circumferential support wall, extends axially beyond at least one blind cavity, preferably beyond each blind cavity, toward the first end side of the outer rotor. This means that the axial extension of the outer rotor can be greater than the axial extension of one blind cavity, and in particular greater than the axial extension of each blind cavity. Alternatively or additionally, the circumferential support wall can, while in sliding contact with the outer rotor, extend axially beyond at least one blind cavity, preferably beyond each blind cavity, toward the first end side of the outer rotor. This means that the axial extension of the circumferential support wall can be greater than the axial extension of one blind cavity, and in particular greater than the axial extension of each blind cavity.

[0031] If the outer rotor and / or the circumferential support wall extend axially beyond at least one blind cavity, preferably each blind cavity, in the sliding contact direction toward the first end side of the outer rotor, the blind cavity, in particular each blind cavity, terminates in a dead end in the region of the outer circumferential surface of the outer rotor in sliding contact and / or in the region of the inner circumferential surface of the circumferential support wall in sliding contact. Thus, one blind cavity, in particular each blind cavity, can be fluidically separated from one or more other blind cavities, in particular in the region of the first end side of the outer rotor.

[0032] The circumferential support wall preferably surrounds the outer rotor in the region of the first end side of the outer rotor in a sliding manner. In particular, the outer circumferential surface of the outer rotor is in sliding contact with the inner circumferential surface of the circumferential support wall over the entire outer circumference of the outer rotor and / or over the entire inner circumference of the circumferential support wall in the region of the first end side of the outer rotor.

[0033] The sliding contact between the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall preferably extends over 360° in the region of the first end side of the outer rotor, so that a radial sealing gap is formed between the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall in the region of the first end side of the outer rotor. The radial sealing gap preferably extends in the axial direction of the outer rotor from the first end side to the second end side thereof over at least 10%, in particular at least 15%, of the axial length of the outer rotor.

[0034] The radial sealing gap between the circumferential support wall and the outer rotor is preferably interrupted by at most one blind cavity and, in particular, is not interrupted by any blind cavity in the region of the first end side of the outer rotor. The radial sealing gap preferably serves to prevent a fluid connection between the blind cavities in the region of the first end side of the outer rotor.

[0035] One blind cavity, preferably each blind cavity, preferably terminates axially at the circumferential support wall on the second end side of the outer rotor and / or at an opening in the outer rotor, i.e., one of the blind cavities, preferably each of the blind cavities, comprises a second end of the cavity, which second end preferably has an opening in the region of the second end side of the outer rotor. The outer rotor and / or the circumferential support wall preferably do not extend axially beyond at least one blind cavity, preferably each blind cavity, in sliding contact with the second end side of the outer rotor.

[0036] The circumferential support wall and the outer rotor are capable of separating respective blind pockets, preferably each blind pocket, from the other blind pockets at their ends, said blind pockets terminating in an opening in a sliding, in particular radial, sliding contact therebetween. The outer circumferential surface of the outer rotor preferably does not contact the inner circumferential surface of the circumferential support wall in the region of the blind pockets, while the outer circumferential surface of the outer rotor and the inner circumferential surface of the circumferential support wall are in sliding, preferably sealing, contact in the region between the blind pockets.

[0037] The housing preferably includes a housing cover that axially delimits the conveying chamber on the second end side of the outer rotor and abuts the circumferential support wall in axially sealing contact. The housing cover can, in particular, form an axial sealing gap with the circumferential support wall. The axial sealing contact between the housing cover and the circumferential support wall preferably extends over the entire circumference of the circumferential support wall in the circumferential direction of the circumferential support wall. The axial sealing contact between the circumferential support wall and the housing cover, in particular the axial sealing contact between the end face of the circumferential support wall formed in the region of the second end side of the outer rotor and the end face of the housing cover facing the circumferential support wall, preferably extends over 360° of the outer circumference of the circumferential support wall in the region of the second end side of the outer rotor. In this way, the blind pockets can be fluidically separated from one another in the region of the second end side of the outer rotor. Preferably, if the blind pockets include ends that terminate in openings in the region of the second end side of the outer rotor, the blind pockets are fluidically separated from one another in the region of the second end side of the pockets by the axial sealing contact, in particular the axial sealing gap.

[0038] The housing cover can rest against the outer rotor in axially sealing sliding contact. Particularly preferably, an axial sealing gap is formed between the second end side of the outer rotor and the housing cover, in particular the end face of the housing cover facing the outer rotor. The housing cover preferably rests against the outer rotor in axially sliding contact, in particular in axially sealing contact. The axial sealing gap between the housing cover and the circumferential support wall can be smaller than the axial sealing gap between the housing cover and the outer rotor.

[0039] 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 side of the outer rotor and the housing cover, in particular the axial sealing gap between the second end side of the outer rotor and the end side of the housing cover facing the outer rotor, preferably extends over 360° around the outer circumference of the outer rotor in the region of the second end side of the outer rotor. In this way, the blind pockets can be fluidically separated from one another in the region of the second end side of the outer rotor. Preferably, if the blind pockets include ends that terminate in an opening in the region of the second end side of the outer rotor, the blind pockets are fluidically separated from one another in the region of the second end side of the pockets by the axial sealing gap.

[0040] The first end side of the outer rotor may include a chamfer along its circumferential outer periphery. The chamfer is preferably formed by ablation of edge material, i.e., the circumferential outer periphery of the outer rotor preferably does not form a sharp edge at its first end side. The chamfer may be rounded, i.e., may have a radius. The chamfer is preferably formed over the entire length of the circumferential outer periphery. The chamfer is preferably at least 200 μm, or at least 300 μm, and / or at most 400 μm, or at most 500 μm, measured in the radial direction. The chamfer is preferably at least 200 μm, or at least 300 μm, and / or at most 400 μm, or at most 500 μm, measured in the axial direction.

[0041] The chamfers, in particular the rotor bevels, can be produced during the manufacture of the outer rotor, in particular during the initial molding of the outer rotor. The outer rotor is preferably manufactured using an initial molding method, such as sintering or casting. In alternative embodiments, the chamfers, in particular the rotor bevels, can be formed by deburring the circumferential outer edge, for example by brushing, grinding, or filing.

[0042] The first end face of the outer rotor particularly preferably comprises a rotor bevel along its circumferential outer periphery. In the context of the present application, a bevel is preferably understood to be a chamfer in the form of an inclination, in particular a plane defined in terms of its width and angle, wherein the inclined surface is preferably curved only in the circumferential direction of the outer rotor.

[0043] The inclined surface, in particular the rotor bevel, can preferably be formed at an angle of 45° to the axial direction of the outer rotor. In an alternative embodiment, the inclined 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 a 45° angle to the axial direction of the outer rotor in both radial and axial directions, with a measurement of at least 300 μm.

[0044] The circumferential support wall may include an inner edge transition along its circumferential inner periphery on the first end side of the outer rotor, i.e., axially relative to the first end side of the outer rotor. The inner edge transition is preferably an overhang of material, i.e., the circumferential inner periphery of the circumferential support wall preferably does not form a sharp edge on the first end side of the outer rotor. The inner edge transition may be rounded, i.e., may have a radius. The inner edge transition is preferably formed along the entire length of the circumferential inner periphery. In particular, if the circumferential support wall is integrally formed with the end wall of the housing, the inner edge transition is formed along the inner edge between the end wall and the circumferential support wall.

[0045] Particularly preferably, the circumferential support wall comprises an inner edge burr along its circumferential inner periphery on the first end side of the outer rotor. In the context of the present application, an inner edge burr is preferably understood to mean an inner edge transition in the form of an inclined, in particular flat, surface that is dimensionally defined with respect to its width and angle, wherein the inclined surface is preferably curved only in the circumferential direction of the circumferential support wall.

[0046] The inner edge transition, in particular the inner edge burr, can be produced during the manufacture of the circumferential support wall, in particular during the initial molding of the circumferential support wall. The circumferential support wall is preferably manufactured as part of the housing cup using an initial molding method, such as sintering or casting. The inner edge transition, in particular the inner edge burr, is preferably formed in a subsequent production step, for example, during machining of the inner circumferential surface of the circumferential support wall by milling, grinding, or honing.

[0047] The inclined surface, in particular the inner edge burr, may preferably form an angle of 45° with the axial direction of the outer rotor and / or the circumferential support wall. In an alternative embodiment, the inclined surface, in particular the inner edge burr, may also form an angle of 60° with the axial direction of the outer rotor and / or the circumferential support wall. The inner edge burr may be formed at any other angle greater than 0° and less than 90° with respect to the axial direction of the outer rotor and / or the circumferential support wall. The inner edge burr is preferably at least 200 μm or at least 300 μm and / or at most 400 μm or 500 μm measured in the radial direction. The inner edge burr is preferably at least 200 μm or at least 300 μm and / or at most 400 μm or at most 500 μm measured in the axial direction. In particular, the inner edge burr is at least 300 μm measured in the radial and axial directions at an angle of 45° with the axial direction of the outer rotor.

[0048] In a particularly preferred embodiment, the outer rotor includes a chamfer, the circumferential support wall includes an inner edge transition, and the chamfer of the outer rotor overlaps the inner edge transition of the circumferential support wall, i.e., the inner edge transition is particularly preferably formed according to the chamfer. It can be said that the inner edge transition forms an imprint or negative of the chamfer. The inner edge transition preferably has the same radius or angle as the chamfer. If the inner edge transition is an inner edge burr, the chamfer is preferably formed as a rotor bevel, wherein the angle relative to the axial direction of the outer rotor and the extension of the inner edge burr in the axial direction are equal to the angle relative to the axial direction of the outer rotor and the extension of the rotor bevel in the axial direction.

[0049] The chamfer is particularly preferably a rotor bevel which is at least 300 μm measured radially and at least 300 μm measured axially at an angle of 45° to the axial direction of the outer rotor, and the inner edge transition is particularly preferably an inner edge burr which is at least 300 μm measured radially and at least 300 μm measured axially at an angle of 45° to the axial direction of the outer rotor.

[0050] In a preferred embodiment, the circumferential support wall includes no chamfer or includes only a small second chamfer along its circumferential inner periphery on the second end side of the outer rotor, and / or the second end side of the outer rotor includes no chamfer or includes only a small second chamfer along its circumferential outer periphery. If the circumferential support wall does not include a chamfer along its circumferential inner periphery on the second end side of the outer rotor and / or the second end side of the outer rotor does not include a chamfer along its circumferential outer periphery, the edge along the circumferential inner periphery of the circumferential support wall and / or along the circumferential outer periphery of the outer rotor is formed as a sharp edge.

[0051] If the circumferential support wall does not include a chamfer or includes only a small second chamfer along the circumferential inner periphery of the second end side of the outer rotor, and / or if the second end side of the outer rotor does not include a chamfer or includes only a small second chamfer along its circumferential outer periphery, at least one blind pocket, and preferably each blind pocket, can terminate axially in an opening in the circumferential support wall and / or the outer rotor on the second end side of the outer rotor. Thus, the missing chamfer or the small second chamfer along the circumferential inner periphery of the circumferential support wall and / or along the circumferential outer periphery of the outer rotor ensures that the blind pockets do not establish a fluid connection, particularly in the form of a fluid flow, along the circumferential inner periphery of the circumferential support wall and / or along the circumferential outer periphery of the outer rotor. If a small second chamfer is provided, the opening along the circumferential inner periphery of the circumferential support wall and / or along the circumferential outer periphery of the outer rotor is preferably sufficiently small that no fluid flow can form between the individual blind pockets.

[0052] A very small second chamfer is preferably understood to mean a deburring process along the circumferential inner periphery of the circumferential support wall and / or along the circumferential outer periphery of the outer rotor, in particular by brushing, filing, or grinding. This means that when a small second chamfer is mentioned, it is the result of a deburring process and not a dimensionally defined slope in terms of its width and angle. This means that if a small second chamfer is provided, it is not a chamfer with a dimensionally defined slope in terms of its width and angle. The small second chamfer preferably has a maximum extent of 100 μm in the axial direction. In particular, the small second chamfer has a maximum extent of 100 μm in the radial direction.

[0053] The first end side of the outer rotor can include a chamfer along its circumferential outer periphery, in particular a rotor bevel, and the second end side of the outer rotor can include a smaller second chamfer along its circumferential outer periphery, wherein the chamfer—in particular the rotor bevel—is at least three times, in particular four times, larger than the second chamfer in the axial direction.

[0054] The circumferential support wall can include an inner edge transition, in particular an inner edge burr, along the circumferential inner periphery of its first end side of the outer rotor, and can include a small chamfer along the circumferential inner periphery of its second end side of the outer rotor, wherein the inner edge transition, in particular the inner edge burr, is at least three times, in particular four times, larger in radial direction than the chamfer of the outer circumferential edge of the first end side of the outer rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The invention will be explained below based on exemplary embodiments. The features disclosed by the exemplary embodiments advantageously form the subject matter of the claims and the above-described embodiments, but do not limit the invention. It is shown that:

[0056] Figure 1 It is a plan view of the conveying space of the rotary pump;

[0057] Figure 2 is an axial section of a rotary pump having a delivery member;

[0058] Figure 3 yes Figure 2 Detailed view of the cross section;

[0059] Figure 4 is the axial section of the outer rotor;

[0060] Figure 5 yes Figure 4 Detailed view of the axial section;

[0061] Figure 6 It is a plan view of the delivery space of the rotary pump without the delivery member;

[0062] Figure 7 is an axial cross-section of a rotary pump without a delivery member; and

[0063] Figure 8 yes Figure 7 Detailed view of the axial section. DETAILED DESCRIPTION

[0064] All figures show a rotary pump and its components in an exemplary embodiment.The present invention is not limited to the exemplary embodiment and can be implemented according to the aforementioned embodiment.

[0065] Figure 1 shows a plan view of the delivery space of the rotary pump, and Figure 2 Shown according to Figure 1 A cross-section of the rotary pump along the axial direction of the rotary pump. Figure 3 Shown Figure 2 Detailed view of Figures 6 to 8 Shown Figure 1 The rotary pump in FIG. 1 is provided, but there is no conveying member 3 or conveying member 4.

[0066] The rotary pump comprises a housing 1 with a delivery chamber 5, which surrounds the delivery chamber and delimits it axially at the end. Figure 2 and Figure 7 As shown, the housing 1 includes a housing cup 11 and a housing cover 12, the housing cover 12 delimiting the delivery space in the axial direction, while the housing cup 11 surrounds the delivery space in the radial direction and axially delimits the delivery space on the side facing away from the housing cover 12, the delivery space 5 including an inlet 6 for the fluid on the low-pressure side of the rotary pump and an outlet 7 for the fluid on the high-pressure side of the pump.

[0067] A delivery member formed in delivery space 5 delivers fluid from the low-pressure side of the rotary pump, particularly inlet 6, to the high-pressure side of the rotary pump, particularly outlet 7. The rotary pump is implemented as an internal gear pump or gerotor pump. The delivery member includes an outer rotor 3 and an inner rotor 4, wherein the outer rotor 3 is formed by an internal gear ring and the inner rotor 4 is formed by an external gear. The teeth of the inner rotor 4 can be moved into engagement with the teeth of the outer rotor 3 by rotating the two rotors. The inner rotor 4 preferably includes one fewer tooth than the outer rotor 3. In this exemplary embodiment, the outer rotor 3 includes five teeth and the inner rotor 4 includes four teeth, wherein the number of teeth is merely exemplary and can vary.

[0068] Due to the meshing between the inner rotor 4 and the outer rotor 3, the two rotors form a conveying unit which, when the two rotors rotate, can change their volume in the circumferential direction of the outer rotor 3. In the present exemplary embodiment, the inner rotor 4 is driven by a drive device, in particular a drive shaft, such as Figure 2 As shown. The inner rotor 4 is mounted so that it can rotate about the pump rotation axis R4 and drives the outer rotor 3, particularly through the meshing of the teeth. The inner rotor 4 is preferably driven by an electric motor. In alternative embodiments, the inner rotor 4 can also be driven by, for example, a component to be supplied. Similarly, in alternative embodiments, the outer rotor 3 can be driven by a drive device, wherein the inner rotor 4 is driven by the outer rotor 3.

[0069] Pump rotation axis R4 of inner rotor 4 is eccentrically formed relative to pump rotation axis R3 of outer rotor 3. That is, pump rotation axis R4 of inner rotor 4 and pump rotation axis R3 of outer rotor 3 are offset. While the eccentricity between pump rotation axis R3 of outer rotor 3 and pump rotation axis R4 of inner rotor 4 is constant in the present exemplary embodiment, it may be variable in alternative embodiments. If the eccentricity between the two pump rotation axes is variable, it can be varied, particularly controlled, depending on, for example, the operating state of the rotary pump.

[0070] The housing cover 11 forms a circumferential support wall 2 surrounding the outer rotor 3 and is mounted so that it can rotate about the pump rotation axis R3 in a sliding contact manner. In an alternative embodiment, the circumferential support wall 2 can also be formed by a separate ring, for example, which is inserted into the delivery space 5. For example, Figure 2 As shown, the circumferential support wall 2 is formed in one piece with the housing cup 11 , in particular with an end wall of the housing cup 11 , in particular in an original moulding method.

[0071] like Figure 1As shown, the circumferential support wall 2 includes blind cavities 21, 22, 23, and 24 that are radially open toward the outer rotor 3 and fluidically separated from one another in the sliding contact region between the outer rotor 3 and the circumferential support wall 2. According to this exemplary embodiment, the rotary pump includes blind cavities 21, 22, 23, and 24 formed in the circumferential support wall 2. In alternative embodiments, the number of blind cavities may vary and is not intended to be limited to four. The blind cavities are fluidically separated from one another at every rotational position of the outer rotor 3, i.e., regardless of the rotational angular position of the outer rotor 3, the blind cavities 21, 22, 23, and 24 are fluidically separated from one another in the radial sliding contact region between the outer rotor 3 and the circumferential support wall 2.

[0072] In an alternative embodiment, blind cavities 21, 22, 23, and 24 are formed in the outer rotor 3 and radially open toward the circumferential support wall 2. Even though blind cavities 21, 22, 23, and 24 are formed in the outer rotor 3, they are fluidly separated from each other in the radial sliding contact area between the outer rotor 3 and the circumferential support wall 2 regardless of the rotational angular position of the outer rotor 3.

[0073] The circumferential support wall 2 surrounds the outer rotor 3 in the region of its first end side 31 in radial sliding contact. In particular, the outer circumferential surface of the outer rotor 3 is in sliding contact with the inner circumferential surface of the circumferential support wall 2 over the entire outer circumference of the outer rotor 3 and / or over the entire inner circumference of the circumferential support wall 2 in the region of its first end side 31, so as to form a radial sealing gap. The radial sealing gap extends in the axial direction of the outer rotor 3 from its first end side 31 to its second end side 32, exceeding at least 10%, in particular at least 15%, of the axial extension of the outer rotor 3.

[0074] like Figure 1 and Figure 6 As shown, blind cavities 21, 22, 23, and 24 are asymmetrically distributed around the circumference of outer rotor 3 relative to the circumferential direction. Specifically, blind cavities 22 and 23 are spaced a certain distance apart from each other around the circumference of outer rotor 3 relative to the circumferential direction, and this distance is greater than the other distances between the blind cavities. For example, the distance between blind cavities 23 and 24 is less than the distance between blind cavities 22 and 23.

[0075] Especially Figure 6As shown, blind cavities 23 and 24 may only overlap with outlet 7 by more than 90% of their circumferential extent in the circumferential direction of outer rotor 3 and / or in the circumferential direction of circumferential support wall 2. In particular, blind cavities 23 and 24 completely overlap with outlet 7 in the circumferential direction of circumferential support wall 2. Blind cavities 21 and 22 may also only overlap with inlet 6 by more than 90% of their circumferential extent in the circumferential direction of outer rotor 3 and / or in the circumferential direction of circumferential support wall 2. In particular, blind cavities 21 and 22 completely overlap with inlet 6 in the circumferential direction of circumferential support wall 2.

[0076] like Figure 2 and Figure 6 As shown, the rotary pump includes four blind cavities, namely blind cavity 21, blind cavity 22, blind cavity 23 and blind cavity 24, which are arranged in a mirror-symmetrical manner with respect to the inner diameter d of the circumferential support wall 2 and / or the outer diameter D of the outer rotor 3, wherein the blind cavity 21 and the blind cavity 22 respectively form a first pair of cavities, and the blind cavities 23 and 24 respectively form a second pair of cavities, wherein the two pairs of cavities are formed in a mirror-symmetrical manner with respect to the inner diameter D of the circumferential support wall 2 and / or the outer diameter D of the outer rotor 3. The symmetry axis of the circumferential support wall 2 and / or the inner diameter d and / or the outer diameter D of the outer rotor 3 is at Figure 6 As indicated by the dotted double arrows, the blind cavities 21 and 22 of the first pair of cavities overlap with the entrance 6 by only more than 80% or more than 90% of their circumferences, and the blind cavities 23 and 24 of the second pair of cavities overlap with the exit 7 by only more than 80% or more than 90% of their circumferences.

[0077] The blind cavities 21, 22, 23 and 24 preferably extend in the circumferential direction of the outer rotor 3 by at least two times, and preferably at least three times, the distance in the radial direction of the outer rotor 3. Figure 3 and Figure 8 As can be seen in the example of the blind cavity 24 in the figure, the axial range of the blind cavity 21, the blind cavity 22, the blind cavity 23, and the blind cavity 24 from the first end 24a of the cavity to the second end 24b of the cavity can correspond to at least 70%, preferably at least 80%, of the axial range of the outer rotor 3 from the first end side 31 to the second end side 32.

[0078] Relative to the circumference of the outer rotor 3, the blind cavities 21, 22, 23, and 24 together have an area 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. That is, the blind cavities 21, 22, 23, and 24 preferably overlap with 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.

[0079] Relative to the outer diameter D of the outer rotor 3 , the blind cavities 21 , 22 , 23 , 24 have a radial extension which preferably corresponds to at most 10%, in particular at most 8%, of the outer diameter D of the outer rotor 3 .

[0080] Especially Figure 3 and Figure 8 As shown in the blind cavity 24 in FIG, the outer rotor 3 extends axially beyond the blind cavity 24 toward its first end side 31 during its sliding contact. Preferably, the outer rotor 3 extends axially beyond the blind cavities 21, 22, 23, and 24 toward its first end side 31 during its sliding contact. According to this exemplary embodiment, the outer rotor 3 extends further in the axial direction than the blind cavities 21, 22, 23, and 24.

[0081] The circumferential support wall 2 also extends axially beyond the blind cavity 24 toward the first end side 31 of the outer rotor 3 in its sliding contact. Preferably, the circumferential support wall 2 extends axially beyond each of the blind cavities 21, 22, 23, and 24 toward the first end side 31 of the outer rotor 3 in its sliding contact. In particular, Figure 3 As shown, the circumferential support wall 2 and the outer rotor 3 have the same axial extent. However, the blind pocket 24 has an axial extent that is smaller than the axial extent of the circumferential support wall 2 and the outer rotor 3.

[0082] Because the outer rotor 3 and the circumferential support wall 2 extend axially beyond the blind cavities 21, 22, 23, and 24 toward the first end side 31 of the outer rotor 3 during their sliding contact, the blind cavities 21, 22, 23, and 24 terminate in a dead end in the region of the outer circumferential surface of the outer rotor 3 in sliding contact and / or in the region of the inner circumferential surface of the circumferential support wall 2 in sliding contact. The outer rotor 3 and the circumferential support wall 2 also form a radial sealing gap in the region of the first end side 31 of the outer rotor 3. This radial sealing gap is not disrupted by any of the blind cavities 21, 22, 23, and 24. In this way, the blind cavities 21, 22, 23, and 24 are fluidically separated from one another in the region of the first end side 31 of the outer rotor 3.

[0083] The blind cavity 24, preferably each of the blind cavities 21, 22, 23, and 24, axially terminates at an opening on the circumferential support wall 2 in the region of the second end side 32 of the outer rotor 3, that is, the blind cavity 24, preferably each of the blind cavities 21, 22, 23, and 24 includes a second end 24b of the cavity in the region of the second end side 32 of the outer rotor 3, which is formed with an opening.

[0084] The outer rotor 3 and the circumferential support wall 2 do not extend axially beyond the blind cavity 24, and preferably do not extend axially beyond each of the blind cavities 21, 22, 23, and 24, in their sliding contact toward the second end side 32 of the outer rotor 3. The circumferential support wall 2 and the outer rotor 3 fluidly separate the blind cavities 21, 22, 23, and 24 from one another at end portions 24b, which terminate in openings, in their sliding contact between the respective blind cavities 21, 22, 23, and 24.

[0085] The housing cover 12 axially delimits the conveying chamber 5 on the second end side 32 of the outer rotor 3. The housing cover 12 rests against the circumferential support wall 2 in axial sealing contact and forms an axial sealing gap with the circumferential support wall 2. The housing cover 12 rests against the outer rotor 3 in axial sliding contact. In particular, the second end side 32 of the outer rotor 3 and the housing cover 12 form an axial sealing gap. The housing cover 12 rests against the outer rotor 3 in axial sliding contact, particularly in axial sealing contact. The axial sealing gap between the housing cover 12 and the circumferential support wall 2 is smaller than the axial sealing gap between the housing cover 12 and the outer rotor 3.

[0086] The axial sealing gap between the housing cover 12 and the circumferential support wall 2 is formed over the entire circumference of the circumferential support wall 2 in the circumferential direction of the outer rotor 3. Thus, the blind pockets 21, 22, 23, and 24 are fluidically separated from one another in the region of the second end side 32 of the outer rotor 3 by the circumferential support wall 2 and the housing cover 12.

[0087] An axial sealing gap is formed between the housing cover 12 and the outer rotor 3 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 side 32 of the outer rotor 3 and the housing cover 12. Thus, the blind cavities 21, 22, 23, and 24 are fluidically separated from one another in the region of the second end side 32 of the outer rotor 3. In particular, because the blind cavities 21, 22, 23, and 24 include open ends 24b that terminate in the region of the second end side 32 of the outer rotor 3, the blind cavities 21, 22, 23, and 24 are fluidically separated from one another in the region of the second ends 24b of the cavities by the axial sealing gap. In particular, the blind cavities 21 , 22 , 23 , and 24 are fluidically separated from one another by an axial sealing gap between the housing cover 12 and the circumferential support wall 2 and an axial sealing gap between the housing cover 12 and the outer rotor 3 in the region of the second end side 32 of the outer rotor 3 .

[0088] like Figure 4 and 5 As particularly shown in FIG. 3 , the first end side 31 of the outer rotor 3 includes a chamfer 31 a along its circumferential outer periphery. Figure 5 As can be seen in the figure, chamfer 31a is formed as a rotor bevel according to the present exemplary embodiment, wherein the rotor bevel preferably has an angle of 45° and extends at least 300 μm in the radial and axial directions. In alternative embodiments, the rotor bevel may also have a different angle, for example, an angle of 60°. In particular, first end side 31 of outer rotor 3 does not include a sharp edge transition between first end side 31 and the outer circumferential surface along its circumferential outer periphery.

[0089] like Figure 8 As specifically disclosed in the circumferential support wall 2, the circumferential support wall 2 includes an inner edge transition 2a along its circumferential inner periphery of the first end side 32 of the outer rotor 3, i.e., on the axial side of the first end side 31 of the outer rotor 3. The inner edge transition 2a can be rounded, i.e., can have a radius. According to this exemplary embodiment, the inner edge transition 2a is formed as an inner edge burr over the entire length of the circumferential inner periphery. The circumferential support wall 2 is formed integrally with the end wall of the housing 1, in particular the housing cup 11, that faces the first end side 31 of the outer rotor 3, and the inner edge transition 2a is formed along the inner edge between the end wall and the circumferential support wall 2.

[0090] The inner edge transition is preferably an inner edge burr of at least 300 μm measured in the radial and axial directions, wherein the inner edge burr has an angle of 45° with the axial direction of the outer rotor 3 .

[0091] When outer rotor 3 is installed, the inner edge burr and rotor bevel 31a overlap each other, that is, the inner edge burr is formed according to the size and angle of the rotor bevel, and / or the rotor bevel 31a is formed according to the size and angle of the inner edge burr. Outer rotor 3 preferably forms a sliding contact with circumferential support wall 2 in the area of rotor bevel 31a.

[0092] The second end side 32 of the outer rotor 3 does not include a chamfer or includes only a small second chamfer 32a. The small second chamfer 32a extends up to 100 μm in the radial and axial directions. The outer circumferential edge 32a of the outer rotor 3 is preferably formed as a sharp edge on its second end side 32.

[0093] If the outer rotor 3 comprises a second small chamfer 32 a on the circumferential outer periphery of its second end side 32 , the second small chamfer 32 a corresponds to at most one third of the first chamfer 31 a .

[0094] Reference Signs List

[0095] 1 shell

[0096] 11 Shell Cup

[0097] 12 housing cover

[0098] 2 circumferential support walls

[0099] 2a Inner edge transition

[0100] 21 blind cyst cavity

[0101] 22 blind cyst cavity

[0102] 23 blind cyst cavity

[0103] 24 blind cyst cavity

[0104] 24a First end of the cyst cavity

[0105] 24b The second end of the cyst cavity

[0106] 3 outer rotor

[0107] 31 first end side

[0108] 31a First chamfer

[0109] 32 second end side

[0110] 32a Second chamfer

[0111] 4 inner rotor

[0112] 5Conveying space

[0113] 6 entrances

[0114] 7Exit

[0115] dInner diameter

[0116] DOuter diameter

[0117] R3 pump rotating shaft

[0118] R4 inner rotor pump shaft

Claims

1. A rotary pump for conveying fluid, comprising: a housing (1) having a delivery space (5), the housing (1) surrounding the delivery space (5) and delimiting the delivery space (5) axially on the end side, and the delivery space (5) comprising an inlet (6) for the fluid on the low-pressure side of the rotary pump and an outlet (7) for the fluid on the high-pressure side of the rotary pump; an inner rotor (4) which is rotatable in the conveying space (5); an outer rotor (3) which is rotatable about a pump rotation axis (R3) in the delivery space (5) and forms a delivery unit with the inner rotor (4); as well as a circumferential support wall (2) formed by the housing (1) or arranged in the housing (1) and surrounding the outer rotor (3) and mounting the outer rotor (3) in radial sliding contact so that the outer rotor (3) can rotate around the pump rotation axis (R3), The circumferential support wall (2) comprises a plurality of blind cavities (21, 22, 23, 24) radially opening toward the outer rotor (3), and / or the outer rotor (3) comprises a plurality of blind cavities (21, 22, 23, 24) radially opening toward the circumferential support wall (2), wherein the blind cavities (21, 22, 23, 24) are fluidically separated from each other in a sliding contact area between the outer rotor (3) and the circumferential support wall (2), and wherein the blind cavities (21, 22, 23, 24) are asymmetrically distributed on the circumference of the outer rotor (3) with respect to the circumferential direction.

2. The rotary pump according to claim 1, wherein The outer rotor (3) and / or the circumferential support wall (2) extend axially in their / their sliding contact toward the first end side (31) of the outer rotor (3) beyond at least one of the blind cavities (21, 22, 23, 24), so that the blind end of each blind cavity (21, 22, 23, 24) terminating at the first end (24a) of the blind cavity is located in the region of the sliding contact of the outer peripheral surface of the outer rotor (3) and / or in the region of the sliding contact of the inner peripheral surface of the circumferential support wall (2), and is therefore fluidically separated from the one or more blind cavities on the first end side (31) of the outer rotor (3).

3. The rotary pump according to claim 2, wherein At least one of the blind cavities (21, 22, 23, 24) ends axially at an opening on the circumferential support wall (2) and / or the outer rotor (3) on the second end side (32) of the outer rotor (3).

4. The rotary pump according to claim 3, wherein The circumferential support wall (2) and / or the outer rotor (3) in their sliding contact separate each of the blind cavities (21, 22, 23, 24) from one or more other blind cavities at their ends, which end in an opening.

5. The rotary pump according to claim 1, wherein The housing (1) comprises a housing cover (12) which axially delimits the conveying space (5) on a second end side (32) of the outer rotor (3), and wherein the housing cover (12) bears against the circumferential support wall (2) in axial sealing contact and / or the housing cover (12) bears against the outer rotor (3) in axial sealing sliding contact.

6. The rotary pump according to claim 1, wherein The housing (1) includes a housing cover (12), which axially delimits the delivery space (5) on the second end side (32) of the outer rotor (3) and forms an axial sealing gap with the circumferential support wall (2) and the outer rotor (3), and wherein the axial sealing gap between the housing cover (12) and the circumferential support wall (2) is smaller than the axial sealing gap between the housing cover (12) and the outer rotor (3).

7. The rotary pump according to claim 1, wherein The first end side (31) of the outer rotor (3) includes a first chamfer (31a) along its circumferential outer periphery and / or the circumferential support wall (2) includes an inner edge transition portion (2a) along the circumferential inner periphery of the circumferential support wall (2) of the first end side (31) of the outer rotor (3).

8. The rotary pump according to claim 7, wherein The first chamfer (31a) on the outer rotor (3) overlaps with the inner edge transition portion (2a) on the circumferential support wall (2).

9. The rotary pump according to claim 7, wherein The second end side (32) of the outer rotor (3) comprises a second chamfer (32a) along its circumferential outer periphery, and the first chamfer (31a) is at least three or four times larger than the second chamfer (32a) in radial and / or axial direction.

10. The rotary pump according to claim 7, wherein The first end side (31) of the outer rotor (3) comprises a first chamfer (31a) along its circumferential outer periphery, and the first chamfer (31a) is measured in the radial direction to be at least 200 μm or at least 300 μm and / or at most 400 μm or 500 μm, and / or wherein the first chamfer (31a) is measured in the axial direction to be at least 200 μm or at least 300 μm and / or at most 400 μm or at most 500 μm.

11. The rotary pump according to claim 1, wherein The circumferential support wall (2) does not include a chamfer or includes only a small second chamfer (32a) along the circumferential inner periphery of the circumferential support wall (2) of the second end side (32) of the outer rotor (3), and / or the second end side (32) of the outer rotor (3) does not include a chamfer or includes only a small second chamfer (32a) along its circumferential outer periphery.

12. The rotary pump according to claim 11, wherein The first end side (31) of the outer rotor (3) includes a first chamfer (31a) along its circumferential outer periphery, and the second end side (32) of the outer rotor (3) includes a second chamfer (32a) along its circumferential outer periphery, and the first chamfer (31a) is at least three times or four times larger than the second chamfer (32a) in the radial and / or axial direction.

13. The rotary pump according to claim 12, wherein The first chamfer (31a) is measured in radial direction at least 200 μm or at least 300 μm and / or at most 400 μm or 500 μm, and / or wherein the first chamfer (31a) is measured in axial direction at least 200 μm or at least 300 μm and / or at most 400 μm or at most 500 μm.

14. The rotary pump according to claim 1, wherein Each of the blind sac cavities (21, 22, 23, 24) overlaps only with the inlet (6) or only with the outlet (7) for more than 80% or 90% of its circumferential length.

15. The rotary pump according to claim 1, wherein The rotary pump comprises four blind cavities (21, 22, 23, 24), and the blind cavities (21, 22, 23, 24) are arranged in a mirror-symmetrical manner with respect to the inner diameter (d) of the circumferential support wall (2) and / or the outer diameter (D) of the outer rotor (3).

16. The rotary pump according to claim 1, characterized in that The distance that the blind sac cavity (21, 22, 23, 24) extends in the circumferential direction of the outer rotor (3) is at least twice or at least three times the distance that the blind sac cavity (21, 22, 23, 24) extends in the radial direction of the outer rotor (3).

17. The rotary pump according to claim 1, wherein The axial length of the blind cavity (21, 22, 23, 24) from the first end (24a) of the blind cavity to the second end (24b) of the blind cavity corresponds to at least 70% or at least 80% of the axial length of the outer rotor (3) from the first end side (31) to the second end side (32).

18. The rotary pump according to claim 2, wherein The outer rotor (3) and / or the circumferential support wall (2) has an axial length exceeding each of the blind cavities (21, 22, 23, 24).

19. The rotary pump according to claim 3, wherein Each of the blind cavities (21, 22, 23, 24) ends axially at an opening on the circumferential support wall (2) and / or the outer rotor (3) on the second end side (32) of the outer rotor (3).

20. The rotary pump according to claim 4, wherein The circumferential support wall (2) and / or the outer rotor (3) separate each blind cavity (21, 22, 23, 24) from one or more other blind cavities by their / their sliding contact at their ends terminating in the opening.

21. The rotary pump according to claim 7, wherein The first chamfer (31a) is a rotor bevel, and / or the inner edge transition (2a) is an inner edge burr.

22. The rotary pump according to claim 14, wherein Each of the blind sac cavities (21, 22, 23, 24) overlaps only with the inlet (6) or only with the outlet (7) within its entire circumferential length.

Images