Electric motor pump

Abstract

The invention relates to an electric motor pump for conveying a liquid, comprising a pump housing which has a suction region and an outlet region and which delimits or forms a pump chamber in which a rotor hollow shaft, which is penetrated by a rotor channel, and a pump conveying wheel for conveying the liquid, are arranged, the pump delivery wheel is mounted on the rotor hollow shaft in a rotationally adjustable manner. The electric motor pump has a cooling circuit which is open towards the pump chamber and which is designed to cool an electric drive motor which is arranged in the motor region of the pump housing and which serves to rotationally drive the pump delivery wheel. Importantly, the electric motor pump has a liquid distributor channel system which is designed to introduce a cooling flow, which flows through the open cooling circuit during operation of the electric motor pump and consists of a liquid, into the pump chamber in an inflow direction, which differs from an axial direction parallel to the central axis.

Description

Field of the Invention

[0001] The present invention relates to an electric motor-driven pump for transporting a liquid as described in the preamble of claim 1. Background Art

[0002] With the aid of the aforementioned electric motor-driven pump, any liquid can be reliably transported at a predefinable volume flow rate, such that the electric motor-driven pump is particularly commonly used in automotive construction, for example for transporting cooling liquid. The disadvantage of these pumps is that the components used therein (such as an electric drive motor and electronic device components) operate in a lossy manner and thus heat up during normal use. Therefore, the pump is equipped with a cooling device according to which the pump can be temperature-controlled and can operate within a predefinable operating temperature window.

[0003] For example, this type of electric motor-driven pump with a cooling device is described in documents EP 3 073 119A1 and US2017 / 0268523A1. Here, the cooling device is designed as an open cooling circuit in which liquid branched off from the delivery flow of the pump is transported as a cooling flow through a cooling channel by means of the pressure difference occurring between the suction region and the outlet region, and this cooling channel runs through the pump. After the cooling flow has passed through the cooling channel and absorbed heat from the component to be cooled, the cooling flow is guided back into the delivery flow again.

[0004] The inventors have found in the course of their development work that undesired hydrodynamic effects occur when guiding the cooling flow back into the delivery flow. For example, vortices are formed in the inflow region of the cooling flow into the delivery flow, and these vortices act like flow barriers and increase the flow resistance of the pump. Here, the flow resistance of the electric motor-driven pump is related to the volume flow rate of the delivery volume and the volume flow rate of the cooling flow, and the following applicable relationship holds: as the volume flow rate increases, the flow resistance in the inlet region also increases. Thus, in the case of known electric motor-driven pumps, particularly when transporting large volume flow rates, large losses occur. That is to say, the hydraulic efficiency of these electric motor-driven pumps is reduced. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide an improved or at least a different embodiment of an electric motor-driven pump.

[0006] In the present invention, this object is solved in particular by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims and the description.

[0007] The basic concept of the present invention is based on the following consideration: It is possible to avoid or at least reduce the undesired hydrodynamic effects or the losses associated therewith, in such a way that the introduction of the coolant into the conveying flow is changed, namely in such a way that the coolant flow guided back into the conveying flow meets the conveying flow at a less hydrodynamically disadvantageous angle.

[0008] For this purpose, the present invention provides an electric motor-driven pump for conveying liquids, in particular an electric motor-driven coolant pump for a vehicle. The proposed electric motor-driven pump has a pump housing which has a suction region and an outlet region and which delimits or forms a pump chamber, into which the suction region and the outlet region open. A first path for the conveying flow consisting of liquid is guided through the suction region, the pump chamber and the outlet region such that the suction region, the pump chamber and the outlet region can be flowed through by the liquid in this order in a suitable manner. Additionally, it is provided that a rotor hollow shaft and a pump impeller for conveying liquid are arranged in the pump chamber, the rotor hollow shaft defining a central axis and being axially penetrated by a rotor channel, and the pump impeller being arranged on the rotor hollow shaft, being rotatably adjustable about the central axis and being drivable in an electric motor-driven manner. Additionally, the electric motor-driven pump has a cooling circuit which is open towards the pump chamber, i.e., is fluidly connected to the pump chamber. Here, the cooling circuit is formed by the rotor channel, a bypass channel and a liquid distributor channel system, the bypass channel fluidly connecting the pump chamber to the rotor channel, and the liquid distributor channel system fluidly connecting the rotor channel to the pump chamber. Additionally, it is provided that a second path for the cooling flow consisting of liquid passes through the cooling circuit such that the bypass channel, the rotor channel and the liquid distributor channel system can be flowed through by the liquid, in particular in this order, for the purpose of cooling an electric drive motor arranged in the motor region of the pump housing and / or control electronics arranged in the motor region, the electric drive motor being used to rotationally drive the pump impeller. What is important for the present invention is that the liquid distributor channel system is designed to introduce the cooling flow flowing through the open cooling circuit during the operation of the electric motor-driven pump into the pump chamber in the inflow direction, the cooling flow consisting of liquid branched off from the conveying flow, and the inflow direction being different from the axial direction parallel to the central axis, i.e., being different from the axial direction oriented parallel to the central axis.

[0009] Thereby, the cooling flow guided back into the pump chamber meets the conveying flow at a more hydrodynamically favorable angle than hitherto, whereby the previously mentioned undesired hydrodynamic effects can be reduced. This has the advantage that, compared to known electric motor-driven pumps, the flow resistance of the pump is particularly significantly reduced. Therefore, the mentioned electric motor-driven pump has a relatively high hydraulic efficiency and can operate in an energy-saving and cost-effective manner, particularly in the case of conveying a large volume flow rate.

[0010] Suitably arranged, the inflow direction extends radially with respect to the central axis. In the sense of the present invention, "radially" or "the inflow direction extends radially with respect to the central axis" means that the inflow direction passes through the central axis and is inclined at an angle with respect to the central axis and is only not parallel to the central axis. Additionally, it can be arranged that the inflow direction extends perpendicularly through the central axis. Thereby, an orientation for the inflow direction is given, in which case the inflow direction passes perpendicularly through the central axis in the radial direction. By means of the given orientation of the inflow direction, the undesired hydrodynamic effects can be further reduced respectively, such that the flow-through resistance of the proposed electric motor-driven pump is further reduced compared to known electric motor-driven pumps.

[0011] The rotor hollow shaft is arranged fixed in position on the pump housing. However, it can be arranged that the rotor hollow shaft is configured as a rotor hollow wheel shaft. In particular, here, the pump impeller is torsionally fixed to the rotor hollow wheel shaft, and the rotor hollow wheel shaft can be rotationally adjusted together with the pump impeller about the central axis.

[0012] It is also advantageous to deflect and orient the inflow direction in the pump impeller or in the rotor hollow shaft such that the cooling flow has a velocity component in the direction of the conveying flow.

[0013] In particular, the inflow direction can form an inflow angle between it and the radial axis perpendicular to the central axis, and this inflow angle is in the angular range between 0° and less than 90°. Thereby, a preferred orientation range for the inflow direction of the cooling flow is given, wherein the orientation for the inflow direction is determined here with respect to the radial axis perpendicular to the central axis. The angular range can preferably be between 0° and 60° and more preferably between 0° and 45°. Thereby, the inflow angle of the cooling flow can be adapted to the flow direction of the conveying flow, and thus a further improvement in the hydraulic efficiency of the proposed pump can be achieved.

[0014] Further suitably, it can be arranged that the inflow direction is oriented parallel or substantially parallel to the flow direction of the conveying flow. Here, during the operation of the electric motor-driven pump, the flow direction of the conveying flow appears in the inflow region of the pump chamber, and the cooling flow is introduced into this inflow region. In this inflow region, the flow direction of the conveying flow can in particular be parallel to the central axis or form an acute angle with the central axis. Thereby, another preferred orientation for the inflow direction is given. This has the advantage that when the cooling flow is introduced into the pump chamber, there is practically no change in the flow direction of the cooling flow, and thus no significant increase in the flow-through resistance occurs in this region. Thereby, the hydraulic efficiency of the proposed pump is optimally adjusted and improved compared to known electric motor-driven pumps.

[0015] The liquid conveyed by the electric motor-driven pump can be formed by a coolant, for example, which involves water, oil or the like. In an open cooling circuit, the conveying flow and the cooling flow are formed by the same liquid.

[0016] Suitably, the electric drive motor can be implemented as a wet rotor For this purpose, the pump chamber is fluidly connected to the motor area. Alternatively, the electric drive motor can be designed as a dry rotor wherein, suitably, the motor area is fluidly separated from the pump chamber. The electric motor-driven pump can have an electronic device component, in particular an electronic device component for controlling the electronic control device, which is particularly used to control the electric drive motor. Here, suitably, the electronic device component can be arranged in the motor area and can be cooled by means of an open cooling circuit. The motor area can form a motor chamber.

[0017] In addition, a bypass channel can extend through at least one stator slot of the stator of the electric drive motor. Thus, the heat generated in the area of the stator during the operation of the electric motor-driven pump can be particularly well absorbed and carried away by the liquid flowing through the bypass channel. In addition, it can be provided that the bypass channel extends at least sectionally through the pump housing. Additionally, it can be provided that the bypass channel extends at least sectionally through the motor area of the pump housing or is at least sectionally formed by the motor area. The bypass channel can be completely or at least sectionally implemented as a single hole or realized by a set of coherent single holes. In addition, the bypass channel can be at least sectionally constructed as an annular channel. In addition, it can be considered that the bypass channel is at least sectionally formed by a free flow area, which is located in a restricted manner between the wall of the motor area and the electric drive motor arranged in the motor area. Additionally, the bypass channel can be formed between the stator of the electric drive motor and the rotor of the electric drive motor.

[0018] Preferably, the pump chamber is divided into a high-pressure section and a low-pressure section by the pump delivery wheel. Herein, from a hydrodynamic perspective, the high-pressure section is arranged between the outflow side of the pump delivery wheel and the outlet region, and from a hydrodynamic perspective, the low-pressure section is arranged between the inflow side of the pump delivery wheel and the suction region. Here, those skilled in the art are aware that the liquid pressure that can be measured in the liquid being conveyed in the high-pressure section is greater than the liquid pressure that can be measured in the liquid being conveyed in the low-pressure section. Suitably, the liquid forming the cooling flow branches off from the high-pressure section of the pump chamber and is guided into an open cooling circuit and into a bypass channel. In addition, the liquid distributor channel system can be provided for guiding the cooling flow into the low-pressure section of the pump chamber. That is to say, after passing through the open cooling circuit, the cooling flow is guided back into the low-pressure section of the pump chamber again by means of the liquid distributor channel system. Herein, suitably, upstream of the liquid inlet for the open cooling circuit in the conveying flow, the liquid is discharged from the open cooling circuit by means of the liquid distributor channel system. Thereby, it can be ensured that a pressure difference occurs between the liquid inlet position and the liquid suction position of the open cooling circuit, and this pressure difference conveys the liquid through the open cooling circuit.

[0019] Additionally, alternatively or additionally, it can be provided that, from a hydrodynamic perspective, after passing through the open cooling circuit, the cooling flow is guided into the compression section of the pump chamber by means of the liquid distributor channel system. From a hydrodynamic perspective, this compression section is arranged between the low-pressure section and the high-pressure section, and the pump delivery wheel is arranged in this compression section.

[0020] The pump delivery wheel can preferably be configured as a radial pump delivery wheel. In the case of this radial pump delivery wheel, the liquid is conveyed from the inflow region located radially inside to the outflow region located radially outside. However, the pump delivery wheel is not necessarily limited to this structural form and can be formed, for example, by an axial pump delivery wheel.

[0021] Suitably, it is provided that the rotor channel opens out at the axial end side of the rotor hollow shaft in the case of forming an overflow opening. This axial end side is arranged in the pump chamber, and a holding device for the rotor hollow shaft is arranged in the pump chamber. This holding device is opposed to the inflow side of the pump delivery wheel facing the suction region and has a receiving portion. The rotor hollow shaft together with its overflow opening, in particular the shaft section of the rotor hollow shaft, is received in the receiving portion. This shaft section has an overflow opening and is arranged in the pump chamber. Herein, the holding device has at least one distributor channel, and the at least one distributor channel forms the liquid distributor channel system. Thereby, a preferred embodiment for an electric motor-driven pump is given, in which the liquid distributor channel system is constructed on the holding device. Herein, the at least one distributor channel can be provided such that the distributor channel guides the cooling flow from the rotor channel into the pump chamber in the inflow direction.

[0022] Here, it is suitably arranged that, in the inflow direction, at least one distributor channel of the holding device extends from the inner surface of the receiving part of the holding device through to the side surface of the holding device facing the pump chamber. Thereby, the rotor channel is fluidly connected to the pump chamber via at least one distributor channel. Thus, the cooling flow can be led out of the open cooling circuit in such a way that the cooling flow flows through the bypass channel and the rotor channel, overflows through the overflow opening of the rotor channel into at least one distributor channel of the liquid distributor channel system, and is then led into the pump chamber through at least one distributor channel.

[0023] Preferably, the holding device is arranged in such a way that it can rotate relative to the pump delivery wheel and / or relative to the rotor hollow shaft. In particular, the holding device is fixedly mounted on the housing in a position-fixed manner.

[0024] In addition to the said axial end side having the overflow opening, suitably, the rotor hollow shaft also has a corresponding axial end side which faces away from the pump chamber and the axial end side of the rotor hollow shaft, and the rotor channel opens out on this corresponding axial end side in the case of a constructed inflow opening. The inflow opening can be arranged, for example, in the motor region. In particular, the shaft section of the rotor hollow shaft having the inflow opening can be arranged in the motor region. Furthermore, the bypass channel can be fluidly connected to the inflow opening of the rotor channel.

[0025] Suitably, the liquid distributor channel system or at least one distributor channel of the liquid distributor channel system can be set up in such a way that the cooling flow is also guided onto the pump delivery wheel or in the direction towards the pump delivery wheel when it is introduced into the pump chamber.

[0026] It is suitably arranged that the holding device has a cone arranged coaxially with respect to the central axis, the apex of the cone facing the suction region, and the receiving part of the holding device opens out at the base of the cone in the case of an insertion opening for the rotor hollow shaft. Carrier arms, which will be described in more detail below, can be arranged on the cone. Suitably, the conical surface of the cone forms the said side surface of the holding device.

[0027] Preferably, half of the opening angle of the cone is at most 35°, in particular at most 30°, in particular less than 30°, in particular at least 10°. Half of such an opening angle has proven to be a good compromise between a favorable inflow and a compact construction of the side surface of the cone or the holding device. In addition, the conical design of the holding device is conducive to the orientation of the inflow direction, such that the cooling flow has a velocity component, in particular its maximum velocity component, in the direction of the delivery flow. Generally preferably, the inflow angle is greater in magnitude than half of the opening angle. In particular, the inflow angle is between 30° and 45°.

[0028] Furthermore, it can be provided that there is provided at least one additional distributor channel, wherein the distributor channel is point-symmetrical about the central axis and / or axially symmetrical about a radial direction perpendicular to the central axis. Thus, the liquid distributor channel system is formed by a plurality of distributor channels, wherein these distributor channels are suitably passed through the holding device such that the distributor channels are point-symmetrical about the central axis and / or axially symmetrical about the radial direction.

[0029] Furthermore, it can be provided that at least one distributor channel has a cross-section or the distributor channels each have a cross-section, wherein the cross-section or the sum of these cross-sections is smaller in area than the cross-section of the overflow opening of the rotor channel. Thereby, preferred cooling can be ensured.

[0030] Furthermore, it is suitably provided that the holding device has a bearing arm by means of which the holding device is fixed to the wall of the pump chamber. Herein, in particular, it can be provided that the holding device and the pump housing are implemented in an integral manner, for example as a casting member, an injection molding member and / or a die-casting member. Suitably, the bearing arms are each constructed in an integral manner with the conical body of the holding device and / or the wall of the pump chamber. In addition, the bearing arms can be designed point-symmetrically about the central axis and / or arranged point-symmetrically about the central axis on the conical body.

[0031] Furthermore, it is suitably provided that the bearing arm has a profile that affects the flow or does not affect the flow. Thereby, the conveying flow can be targeted affected when needed.

[0032] It is suitably provided that the pump delivery wheel has a sliding bearing ring and the holding device has a corresponding sliding bearing ring, wherein the rotor hollow shaft is supported on the corresponding sliding bearing ring of the holding device about the central axis axially and / or radially via the sliding bearing ring. Thus, the rotor hollow shaft is supported on the holding device. Suitably, it can be provided that the receiving portion of the holding device is implemented stepwise. Herein, the corresponding sliding bearing ring of the holding device can be arranged in the first step of the receiving portion of the holding device, and this first step abuts against the insertion opening of the receiving portion of the holding device. In addition, at least one distributor channel or these distributor channels of the holding device can open into the receiving portion of the holding device in or on the region of the second step of the holding device, and this second step is adjacent to the first step.

[0033] Generally preferably, the distributor channels of the holding device are completely arranged on the side of the corresponding sliding bearing ring that points away from the sliding bearing ring in the axial direction. The corresponding sliding bearing ring can thus be arranged between the respective distributor channel and the sliding bearing ring. This ensures the conventional co-action of the sliding bearing ring and the corresponding sliding bearing ring. In particular, at least one region of the distributor channel is directly delimited by the corresponding sliding bearing ring.

[0034] In particular, at least one distributor channel, in particular these distributor channels, respectively open towards the pump delivery wheel on the side surface of the holding device in the axial direction. Thereby, the velocity component of the cooling flow in the direction of the delivery flow can be maximal. Additionally or alternatively, in particular, the distributor channels are respectively delimited sectionally in the axial direction and perpendicular to this axial direction, i.e., radially, by the corresponding sliding bearing ring.

[0035] In an alternative embodiment of the invention, it is expediently provided that the liquid distributor channel system is constructed on or by means of the rotor hollow shaft. Here, the liquid distributor channel system can be realized by at least one distributor channel that penetrates the rotor hollow shaft and is set up such that this distributor channel conducts the cooling flow from the rotor channel into the pump chamber in the inflow direction.

[0036] In another alternative embodiment of the invention, it is expediently provided that the liquid distributor channel system is constructed on or by means of the pump delivery wheel. Here, the liquid distributor channel system can expediently be constructed by means of the rotor channel and / or channels or chambers within the pump delivery wheel. Thereby, another preferred embodiment of the electric motor-driven pump is given, according to which the cooling flow can be conducted from the rotor channel into the pump chamber in the inflow direction.

[0037] In summary, it should be noted that: Preferably, the present invention relates to an electric motor-driven pump for transporting a liquid, the electric motor-driven pump having a pump housing which has a suction region and an outlet region and which delimits or forms a pump chamber, wherein a rotor hollow shaft and a pump impeller for transporting the liquid are arranged in the pump chamber, the rotor hollow shaft being penetrated by a rotor channel, and the pump impeller being rotatably adjustable and supported on the rotor hollow shaft. The electric motor-driven pump has a cooling circuit which is open towards the pump chamber, the open cooling circuit being provided for cooling an electric drive motor and / or control electronics arranged in a motor region of the pump housing, the electric drive motor being used to rotationally drive the pump impeller. What is important for the present invention is that the electric motor-driven pump has a liquid distributor channel system which is provided for introducing a cooling flow composed of liquid, which flows through the open cooling circuit during operation of the electric motor-driven pump, into the pump chamber in an inflow direction which is different from an axial direction parallel to the central axis of the rotor hollow shaft.

[0038] Other important features and advantages of the present invention result from the dependent claims, the drawings and the associated description of the drawings.

[0039] It should be understood that the features mentioned above and to be explained below can be used not only in the correspondingly given combinations, but also in other combinations or individually, without departing from the framework of the present invention. Description of the Drawings

[0040] Preferred embodiments of the present invention are shown in the drawings and are explained in more detail in the following description, where the same reference numerals refer to the same or similar or functionally identical components.

[0041] The drawings schematically show:

[0042] Figure 1 A longitudinal sectional view showing a preferred embodiment of an electric motor-driven pump according to the present invention,

[0043] Figure 2 showing Figure 1 a fragment according to the small box drawn in dashed lines therein,

[0044] Figure 3 showing Figure 1 a different longitudinal sectional view of the electric motor-driven pump in, wherein the section passes through the bearing arm of the holding device,

[0045] Figure 4 showing Figure 1 a perspective view of the holding device of the electric motor-driven pump in,

[0046] Figure 5 and 6 respectively show Figure 1 a perspective view from the obliquely rear of the holding device of the electric motor-driven pump in , where, in order to better see the holding device, the rotor hollow shaft and the rotor are respectively particularly hidden. Detailed implementation manner

[0047] Figures 1 to 6 shows a preferred implementation manner of the electric motor-driven pump according to the present invention. The electric motor-driven pump is generally denoted by the reference numeral 1 in the drawings. According to this implementation manner, any liquid, such as water or the like, can be reliably conveyed with a pre-given volume flow rate. For example, this can relate to an electric motor-driven cooling pump for a vehicle that can be used in automotive construction. Here, the application field of the proposed electric motor-driven pump 1 is not limited to this.

[0048] Purely by way of example, the electric motor-driven pump 1 according to Figure 1 has a multi-piece pump housing 2, which has at least one suction region 3, an outlet region 4, a housing upper part 46 and a housing lower part 47 arranged on the housing upper part 46. The at least one suction region has two separate inlets 51, 52. The housing upper part 46 of the pump housing 2 limits or forms a pump chamber 5, and the suction region 3 and the outlet region 4 lead into this pump chamber. A first path 7 for the conveying flow 8 composed of liquid passes through the suction region 3, the pump chamber 5 and the outlet region 4. This first path is marked by a dotted line, where the suction region 3, the pump chamber 5 and the outlet region 4 can be flowed through by the liquid in this order. In Figure 1 it can also be seen that in the pump chamber 5, a shaft section of the rotor hollow shaft 11 and a pump delivery wheel 12 for conveying liquid are arranged. The rotor hollow shaft is axially penetrated by a rotor channel 10. The pump delivery wheel can be rotationally adjusted around a central axis 9 on the rotor hollow shaft 11 and can be driven in an electric motor manner. In the present case, the pump delivery wheel 12 is configured as a radial pump delivery wheel and divides the pump chamber 5 into a high-pressure section 25 and a low-pressure section 24. The high-pressure section 25 is arranged between the outflow side 48 of the pump delivery wheel 12 and the outlet region 4, and the low-pressure section 24 is arranged between the inflow side 30 of the pump delivery wheel 12 and the suction region 3. A compression section 26 is arranged hydrodynamically between the low-pressure section 24 and the high-pressure section 14, and the pump delivery wheel 12 is located in this compression section. The rotor hollow shaft 11 has an axial end side 27 on the shaft section thereof arranged in the pump chamber 5, and the rotor channel 10 leads out at this axial end side in the case of a constructed overflow opening 28.

[0049] The housing lower part 47 of the pump housing 2 delimits or forms the motor region 6, which is arranged above the pump chamber 5 and in which an electric drive motor 18 is arranged for rotationally driving the pump impeller 12. Here, an electronic device component for controlling the electric drive motor 18 is arranged in the motor region 6, and the electronic device component is generally designated by 49. The rotor hollow shaft 11 has a corresponding axial end side 35 on its further shaft section, which is remote from the pump chamber 5 and the axial end side 27 of the rotor hollow shaft 11 and is arranged in the motor region 6, and the rotor channel 10 opens out on this corresponding axial end side in the case of a configured inflow opening 36. It can also be seen that a supply attachment end 50 is arranged on the housing lower part 47, by means of which the electric drive motor 18 and the electronic device component 49 are supplied with electrical energy and information can be exchanged, for example, with an external control unit not shown here. The housing upper part 46 and the housing lower part 47 are fixed to one another in a fluid-tight and releasable manner, for example by means of fastening screws and sealing devices, which are, for example, sealing strips or the like.

[0050] During normal operation of the electro-motor-driven pump 1, the electric drive motor 18 and the electronic device component 49 heat up. Therefore, the electro-motor-driven pump 1 is equipped with a cooling circuit 13 that is open towards the pump chamber 5 or towards the conveying flow 8, by means of which the electric drive motor 18 and / or the electronic device component 49 can be cooled and kept within a pre-defined operating temperature window.

[0051] Here, the open cooling circuit 13 is formed by the rotor channel 10, the bypass channel 14, which fluidly connects the pump chamber 5 to the rotor channel 10, and the liquid distributor channel system 15, which fluidly connects the rotor channel 10 to the pump chamber 5. In the present case, the bypass channel 14 extends at least sectionally through the housing lower part 47 of the pump housing 2 and / or at least sectionally through the motor region 6. A second path 16 for the cooling flow 17 formed by the liquid extends through the open cooling circuit 13. When the electro-motor pump 1 is operating, the liquid branched off from the pump chamber 5 at the inlet 53 of the open cooling circuit 13 can flow as the cooling flow 17 first into the bypass channel 14. Then, the cooling flow 17 completely traverses the bypass channel 14 and enters the rotor channel 10 via the inflow opening 36. The cooling flow 17 completely traverses the rotor channel 10 and enters the liquid distributor channel system 15 via the overflow opening 28, such that the cooling flow 17 is then guided back into the pump chamber 5 again at the outlet 54 of the open cooling circuit 13 by means of the liquid distributor channel system 15. The cooling flow 17 absorbs heat from the components to be cooled of the electro-motor pump 1 along the second path, and this heat is then guided together with the cooling flow 17 into the pump chamber 5 and discharged from the electro-motor pump 1 together with the delivery flow 8. Here, the open cooling circuit 13 is designed such that the liquid is conveyed through the rotor channel 10, the bypass channel 14, and the liquid distributor channel system 15 by means of the pressure difference occurring between the inlet 53 and the outlet 54. For this purpose, the outlet 54 is arranged upstream of the inlet 54 in the delivery flow 8, for example in the low compression section 24 or in the compression section 25 of the pump chamber 5.

[0052] In the present case, the liquid distributor channel system 15 is configured to introduce the cooling flow 17 flowing through the open cooling circuit 13 during operation of the electro-motor pump 1 into the pump chamber 5 in a pre-given inflow direction 19. Here, the inflow direction 19 is different from the axial direction 20 parallel to the central axis, i.e., the axial direction 20 oriented parallel to the central axis 9. The inflow direction 19 preferably extends radially with respect to the central axis 9 and can in particular be perpendicular to the central axis 9. Further preferably, the inflow direction 19 extends parallel or substantially parallel to the flow direction 22 of the delivery flow 8, which occurs in the inflow region 23 of the pump chamber 5 during operation of the electro-motor pump 1 and into which the cooling flow 17 is introduced. Depending on the orientation of the inflow direction 19, the cooling flow 17 is introduced into the pump chamber 5 such that it meets the delivery flow 8 at a hydraulically more favorable angle than hitherto. Thereby, undesired hydrodynamic effects, such as vortices or the like, are reduced, such that the flow resistance of the electro-motor pump 1 is decreased and a relatively high hydraulic efficiency is achieved.

[0053] InFigures 1 to 6 As can be seen, a retaining device 29 for the hollow rotor shaft 11 is arranged in the low-pressure section 24 of the pump chamber 5. The retaining device is opposed to the inflow side 30 of the pump delivery wheel 12 facing the suction region 3 and has a receiving portion 31 in which the hollow rotor shaft 11 together with its overflow opening 28 is received. The retaining device 29 has a conical body 37 arranged coaxially with respect to the central axis 9 or is formed by the conical body. The conical body has an apex 38 and a base 55, the apex facing the suction region 3, and the receiving portion 31 of the retaining device 29 opens out at the base in the case of an insertion opening 39 configured for the hollow rotor shaft 11. Furthermore, in Figures 1 to 6 As can be seen, the retaining device 29 is fixed to the wall portion 41 of the housing upper part 46 by means of three integral load-bearing arms 40. In the present case, the receiving portion 31 is implemented stepwise and has a first step 44 which abuts against the insertion opening 39 of the receiving portion 31, and a corresponding sliding bearing ring 43 is received and fixed in the first step. The pump delivery wheel 12 has a sliding bearing ring 42, wherein the pump delivery wheel 12 is supported axially and / or radially with respect to the central axis 9 on the corresponding sliding bearing ring 43 of the retaining device 29 and / or on the hollow rotor wheel shaft 11 via the sliding bearing ring 42. In the present case, the retaining device 29 has a plurality of distributor channels 32a, 32b, 32c which together form the liquid distributor channel system 15. Here, in the inflow direction 19, the distributor channels 32a, 32b, 32c extend from the first step 44 through the inner surface 33 of the receiving portion 31 of the retaining device 29 through the retaining device 29 or the conical body 37 of the retaining device 29 to the side surface 34 of the retaining device 29 facing the pump chamber 5, whereby the distributor channels can introduce the cooling flow 17 from the rotor channel 10 into the pump chamber 5 in the inflow direction 19. In Figure 5 and 6 As can be seen, the distributor channels 32a, 32b, 32c are point-symmetric with respect to the central axis 9 and / or axisymmetric with respect to a radial direction perpendicular to the central axis 9. Here, the retaining device 29 is implemented such that the distributor channels 32a, 32b, 32c open out axially on the side surface 34 towards the pump delivery wheel 12. Thereby, the velocity component of the cooling flow is maximum in the direction of the delivery flow during operation.

Claims

1. An electric motor pump (1) for conveying a liquid, in particular an electric motor cooling pump for a vehicle, the electric motor pump has a pump housing (2), which has a suction region (3) and an outlet region (4), and the pump housing delimits or forms a pump chamber (5), into which the suction region (3) and the outlet region (4) open, -in, A first path (7) for a delivery flow (8) consisting of a liquid passes through the intake region (3), the pump chamber (5) and the outlet region (4), so that the liquid can flow through the intake region (3), the pump chamber (5) and the outlet region (4). - wherein a rotor hollow shaft (11) and a pump delivery wheel (12) for delivering a liquid are arranged in the pump chamber (9), the rotor hollow shaft defining a central axis (9) and being penetrated in the axial direction by a rotor channel (10), the pump delivery wheel being supported on the rotor hollow shaft (11), being rotatably adjustable about the central axis (9) and being drivable in the manner of an electric motor, wherein the electric motor pump (1) has a cooling circuit (13) which is open toward the pump chamber (5), the open cooling circuit being formed by the rotor channel (10), a bypass channel (14) which fluidically connects the pump chamber (5) with the rotor channel (10), and a liquid distributor channel system (15) which fluidically connects the rotor channel (10) with the pump chamber (5), wherein a second path (16) for a cooling flow (17) consisting of a liquid passes through the open cooling circuit (13), so that liquid can flow through the bypass channel (14) and the rotor channel (10) for the purpose of cooling an electric drive motor (18) arranged in the motor region (6) of the pump housing (2), and liquid can flow through the liquid distributor channel system (15), the electric drive motor being used to rotationally drive the pump delivery wheel (12), -Wherein, the liquid distributor channel system (15) is designed to direct a cooling flow (17) flowing through the open cooling circuit (13) during operation of the electric motor pump (1) into the pump chamber (5) in an inflow direction (19), wherein the cooling flow is composed of liquid branched off from the delivery flow (8), the inflow direction being different from an axial direction (20) parallel to the central axis.

2. The electric motor pump (1) according to claim 1, It is characterized in that The inflow direction (19) extends radially with respect to the central axis (9).

3. The electric motor pump (1) according to claim 1 or 2, It is characterized in that The inflow direction (19) extends perpendicularly with respect to the flow direction of the cooling flow (17) in the rotor channel (10).

4. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that The inflow direction (19) is oriented parallel or substantially parallel to the flow direction (22) of the delivery flow (8).

5. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that The liquid distributor channel system (15) is designed to conduct the cooling flow (17) into a low-pressure section (24) of the pump chamber (5), which is arranged axially between an inflow side (30) of the pump delivery wheel (12) and the suction region (3).

6. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that the rotor channel (10) opens out at an axial end side (27) of the hollow rotor shaft (11) with the formation of an overflow opening (28), the axial end side being arranged in the pump chamber (5), wherein a holding device (29) for the hollow rotor shaft (11) is arranged in the pump chamber (5), the holding device being situated opposite an inflow side (30) of the pump delivery wheel (12) facing the intake region (3) and having a receptacle (31) in which the hollow rotor shaft (11) is received together with its overflow opening (28), - wherein the holding device (29) has at least one distributor channel (32a, 32b, 32c) which forms the liquid distributor channel system (15).

7. The electric motor pump (1) according to claim 6, It is characterized in that In the inflow direction (19), the at least one distributor channel (32a, 32b, 32c) runs through the retaining device (29) from an inner surface (33) of a receiving portion (31) of the retaining device (29) to a side surface (34) of the retaining device (29) facing the pump chamber (5).

8. The electric motor pump (1) according to claim 6 or 7, It is characterized in that - at least one further distributor channel (32a, 32b, 32c) is provided, - wherein the distributor channels (32a, 32b, 32c) are point-symmetrical about the central axis (9).

9. The electric motor pump (1) according to any one of claims 6 to 8, It is characterized in that The holding device (29) has a supporting arm (40) by means of which the holding device (29) is fastened to a wall (41) of the pump chamber (5).

10. The electric motor pump (1) according to claim 9, It is characterized in that The support arm (40) has a flow-sensitive or flow-insensitive profile.

11. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that The liquid distributor channel system (15) is formed on or through the hollow rotor shaft (11).

12. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that The liquid distributor channel system (15) is formed on or by the pump delivery wheel (12).

13. The electric motor pump (1) according to any one of the preceding claims, It is characterized in that the pump delivery wheel (12) has a plain bearing ring (42) and the retaining device (29) has a corresponding plain bearing ring (43), wherein the pump delivery wheel (12) is supported via the plain bearing ring (42) axially and / or radially with respect to the central axis (9) on a corresponding plain bearing ring (43) of the retaining device (29) and / or on the rotor hollow shaft (11).

14. The electric motor pump (1) according to claim 13, It is characterized in that The distributor channels (32a, 32b, 32c) of the retaining device (29) are arranged completely on the side of the counter plain bearing ring (43) which points away from the plain bearing ring (42) with respect to the axial direction (20).

15. The electric motor pump (1) according to any one of claims 6 to 14, It is characterized in that The retaining device (29) has a cone arranged coaxially with respect to the center axis (9), the cone top of which faces the intake region, and the receiving portion (31) of the retaining device (29) opens out at the cone bottom of the cone while forming an insertion opening for the hollow rotor shaft (11).

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