Electromotive pump

Abstract

The present invention relates to an electromotive pump (1) for conveying a liquid, comprising a pump housing (2) which has an intake region (3) and an outlet region (4) and delimits or forms a pump chamber (5), wherein a hollow rotor shaft (11) through which a rotor channel (10) passes and a pump impeller (12) mounted rotatably on the hollow rotor shaft for conveying liquid are arranged in the pump chamber (5). The electromotive pump (1) has a cooling circuit (13) which is open to the pump chamber (5) and is designed to cool an electric drive motor (18) which is arranged in a motor region (6) of the pump housing (2) and which rotates the pump impeller (12).It is essential for the invention that the electromotive pump (1) has a liquid distribution channel system (15) which is designed to introduce a cooling flow (17) of liquid, which flows through the open cooling circuit (13) during operation of the electromotive pump (1), into the pump chamber (5) in an inflow direction (19) which is different from an axial direction (20) parallel to the center axis.

Description

[0001] The invention relates to an electromotive pump for conveying a liquid according to the preamble of claim 1.

[0002] Using the aforementioned electric motor pump, any liquid can be pumped reliably and at preset flow rates, making them particularly popular in automotive engineering, for example, for pumping coolant. The disadvantage of these pumps is that the components used in them, such as electric drive motors and electronic components, operate with losses and therefore heat up during normal use. Pumps are therefore equipped with cooling devices that allow them to be controlled and operated within a specified operating temperature range.

[0003] Electromotive pumps with cooling devices of this type are described, for example, in documents EP 3 073 119 A1 and US 2017 / 0268523 A1. The cooling devices are designed as open cooling circuits in which liquid branched from a pump flow is conveyed as a cooling flow through a cooling channel passing through the pump by means of a pressure difference established between an intake area and an outlet area. After the cooling flow flows through the cooling channel and absorbs heat from the components to be cooled, it is redirected back into the flow.

[0004] During their development work, the inventors discovered that undesirable fluid mechanics effects occur when the cooling flow is returned to the delivery flow. For example, turbulence forms in the inlet area of ​​the cooling flow into the delivery flow, acting as flow barriers and increasing the flow resistance of the pump. The flow resistance of the electromotive pump is dependent on the volumetric flow of the delivery flow and the volumetric flow of the cooling flow, with the relationship that the flow resistance in the inlet area increases with increasing volumetric flows. This results in large losses in known electromotive pumps, particularly when pumping large volumetric flows. This means that the hydraulic efficiency of these electromotive pumps is reduced.

[0005] The object of the invention is therefore to provide an improved or at least a different embodiment of an electromotive pump.

[0006] In the present invention, this object is achieved 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 idea of ​​the invention is based on the consideration that the said undesirable fluid-mechanical effects or the associated losses can be avoided or at least reduced by changing the introduction of the coolant into the conveying flow, namely in such a way that the cooling flow returned to the conveying flow and the conveying flow meet at a fluid-mechanically less unfavorable angle.

[0008] To this end, the invention proposes the following electromotive pump for conveying a fluid, in particular an electromotive cooling pump for a vehicle. The proposed electromotive pump has a pump housing that has an intake region and an outlet region and delimits or forms a pump chamber into which the intake region and the outlet region open. A first path for a conveying flow of fluid is led through the intake region, the pump chamber, and the outlet region, so that fluid can expediently flow through the intake region, the pump chamber, and the outlet region in this order.Furthermore, it is provided that a hollow rotor shaft defining a central axis and axially penetrated by a rotor channel, as well as an electric motor-driven pump impeller for pumping fluid, arranged on the hollow rotor shaft, rotatably adjustable about the central axis, are arranged in the pump chamber. The electric motor-driven pump further has a cooling circuit open to the pump chamber, i.e., fluidically connected to the pump chamber. The cooling circuit is formed by the said rotor channel, a bypass channel fluidically connecting the pump chamber to the rotor channel, and a fluid distribution channel system fluidically connecting the rotor channel to the pump chamber.Furthermore, it is provided that a second path for a cooling flow of liquid leads through the cooling circuit, so that, in particular in this order, the bypass channel, the rotor channel and the liquid distribution channel system can be flowed through by liquid for the purpose of cooling an electric drive motor arranged in a motor region of the pump housing for rotating the pump impeller and / or control electronics arranged in the motor region. It is essential for the invention that the liquid distribution channel system is designed to introduce a cooling flow of liquid, which is branched off from the delivery flow and flows through the cooling circuit during operation of the electromotive pump, into the pump chamber in an inflow direction which is different from an axial direction parallel to the center axis, i.e. an axial direction aligned parallel to the center axis.

[0009] As a result, the cooling flow returned to the pump chamber meets the flow at a more fluidically favorable angle than before, thus reducing the aforementioned undesirable fluid dynamic effects. This has the advantage that, in particular, the flow resistance of the pump is significantly reduced compared to known electromotive pumps. The proposed electromotive pump therefore has a comparatively high hydraulic efficiency and can be operated energy-efficiently and cost-effectively, especially when pumping large volume flows.

[0010] It is expediently provided that the inflow direction runs radially with respect to the center axis. For the purposes of this invention, "radial" or "the inflow direction runs radially with respect to the center axis" means that the inflow direction runs through the center axis and is tilted at an angle with respect to the center axis and is merely not parallel to the center axis. It can also be provided that the inflow direction runs perpendicularly through the center axis. This specifies an orientation for the inflow direction in which the inflow direction runs radially perpendicularly through the center axis. Based on the specified orientations of the inflow direction, undesirable fluid-mechanical effects can be further reduced, so that the flow resistance of the proposed electromotive pump is further reduced compared to known electromotive pumps.

[0011] The hollow rotor shaft is fixedly mounted on the pump housing. However, it could be provided that the hollow rotor shaft is designed as a hollow rotor shaft. In particular, the pump impeller is fixed to the hollow rotor shaft in a rotationally fixed manner, and the hollow rotor shaft, together with the pump impeller, is rotationally adjustable relative to the center axis.

[0012] It would also be advantageous to redirect and align the inflow direction in the pump impeller or in the rotor hollow axis so that the cooling flow has a velocity component in the direction of the flow.

[0013] In particular, the inflow direction can span an inflow angle between itself and a radial axis perpendicular to the central axis, which lies in the angular range between 0° and less than 90°. This specifies a preferred orientation range for the inflow direction of the cooling flow, wherein the orientation for the inflow direction is determined this time with respect to a radial direction perpendicular to the central axis. This angular range can preferably lie between 0° and 60° and more preferably between 0° and 45°. This allows the inflow angle of the cooling flow to be adapted to a flow direction of the delivery flow, thus further improving the hydraulic efficiency of the proposed pump.

[0014] It can further be expediently provided that the inflow direction is aligned parallel or substantially parallel with respect to said flow direction of the conveying flow. The flow direction of the conveying flow is established during operation of the electromotive pump in an inflow region of the pump chamber into which the cooling flow is introduced. The flow direction of the conveying flow in this inflow region can be parallel, in particular with respect to the central axis, or form an acute angle with the central axis. This specifies a further preferred orientation for the inflow direction. 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 resistance in this region.As a result, the hydraulic efficiency of the proposed pump is optimally adjusted and improved compared to known electromotive pumps.

[0015] The fluid pumped by the electric motor pump can be a coolant, such as water, oil, or the like. In an open cooling circuit, the delivery flow and the cooling flow are formed by the same fluid.

[0016] Said electric drive motor can expediently be designed as a wet-running motor. For this purpose, the pump chamber is fluidically connected to the motor area. Alternatively, the electric drive motor can be designed as a dry-running motor, wherein the motor area is expediently fluidically separated from the pump chamber. The electromotive pump can have electronic components, in particular electronic components of the control electronics, in particular for controlling the electric drive motor. The electronic components can expediently be arranged in the motor area and can be cooled by means of the open cooling circuit. The motor area can form a motor chamber.

[0017] Furthermore, the bypass channel can extend through at least one stator slot of a stator of the electric drive motor. This allows heat generated in the region of the stator during operation of the electric motor pump to be absorbed and transported away particularly well by the fluid flowing through the bypass channel. It can also be provided that the bypass channel extends at least partially through the pump housing. Furthermore, it can be provided that the bypass channel extends at least partially through the motor region of the pump housing or is formed at least partially by the motor region. The bypass channel can be implemented entirely or at least partially as a single bore or by a group of connected individual bores. The bypass channel can also be designed at least partially as an annular channel.It is further conceivable that the bypass channel is formed, at least in sections, by a free flow area that is delimited between a wall of the motor area and the electric drive motor arranged in the motor area. Furthermore, the bypass channel can be formed between said stator of the electric drive motor and a rotor of the electric drive motor.

[0018] It is expedient if the pump chamber is divided by the pump impeller into a high-pressure section and a low-pressure section, wherein the high-pressure section is arranged, in terms of flow, between a downstream side of the pump impeller and the outlet region, and the low-pressure section is arranged, in terms of flow, between an upstream side of the pump impeller and the intake region. It is clear to a person skilled in the art that a fluid pressure measurable in the pumped fluid within the high-pressure section is greater than a fluid pressure measurable in the pumped fluid within the low-pressure section. The fluid forming the cooling flow is expediently branched off from the high-pressure section of the pump chamber and guided into the open cooling circuit in the bypass channel. Furthermore, the fluid distribution channel system can be configured to introduce the cooling flow into a low-pressure section of the pump chamber. That is,After flowing through the open cooling circuit, the cooling flow is redirected back to the low-pressure section of the pump chamber via the fluid distribution channel system. The fluid outlet from the open cooling circuit via the fluid distribution channel system is preferably located upstream of a fluid inlet for the open cooling circuit. This ensures that a pressure difference is established between the fluid inlet point and the fluid intake point of the open cooling circuit, which pumps the fluid through the open cooling circuit.

[0019] Furthermore, alternatively or additionally, it can be provided that the cooling flow, after flowing through the open cooling circuit, is introduced by means of the liquid distribution channel system into a compression section of the pump chamber, which is arranged fluidically between the low-pressure section and the high-pressure section and in which the pump impeller is arranged.

[0020] The pump impeller can preferably be designed as a radial pump impeller. In this case, the fluid is conveyed from a radially inner inflow area to a radially outer outflow area. However, the pump impeller is not necessarily limited to this design and can, for example, be formed by an axial pump impeller.

[0021] It is expediently provided that the rotor channel opens out at an axial end face of the hollow rotor shaft arranged in the pump chamber, forming an overflow opening, wherein a holding device for the hollow rotor shaft is arranged in the pump chamber, which holding device is opposite an upstream side of the pump impeller facing the intake region and has a receptacle in which the hollow rotor shaft is received together with its overflow opening, in particular an axle section of the hollow rotor shaft arranged in the pump chamber and having the overflow opening. The holding device can have at least one distribution channel which forms the liquid distribution channel system. This specifies a preferred embodiment of the electromotive pump in which the liquid distribution channel system is formed on the holding device.The at least one distribution channel can be designed such that it introduces the cooling flow from the rotor channel into the pump chamber in the inflow direction.

[0022] In this case, it is expediently provided that the at least one distribution channel of the holding device extends in the inflow direction from an inner surface of the receptacle of the holding device to a lateral surface of the holding device facing the pump chamber. As a result, the rotor channel is fluidly connected to the pump chamber via the at least one distribution channel. As a result, the cooling flow can be discharged from the open cooling circuit by the cooling flow flowing through the bypass channel and the rotor channel, flowing via the overflow opening of the rotor channel into the at least one distribution channel of the liquid distribution channel system, and then being introduced through the at least one distribution channel into the pump chamber.

[0023] In addition to the aforementioned axial end face with overflow opening, the hollow rotor shaft expediently has a counter-axial end face facing away from the pump chamber and the axial end face of the hollow rotor shaft, at which the rotor channel opens to form an inflow opening. The inflow opening can be arranged, for example, in the motor region. In particular, an axial section of the hollow rotor shaft having the inflow opening can be arranged in the motor region. Furthermore, the bypass channel can be fluidically connected to the inflow opening of the rotor channel.

[0024] The liquid distribution channel system or the at least one distribution channel of the liquid distribution channel system can expediently be designed such that the cooling flow is directed onto the pump impeller or in the direction of the pump impeller when introduced into the pump chamber.

[0025] It is expedient for said holding device to have a conical body arranged coaxially with respect to the central axis, the conical tip of which faces the intake area or the flow direction of the conveyed stream, and at the conical base of which the receptacle for the holding device opens, forming an insertion opening for the hollow rotor shaft. Support arms, as described below, can be arranged on the conical body. The conical surface of the conical body expediently forms the said surface area of ​​the holding device.

[0026] It may further be provided that at least one further distribution channel is provided, wherein the distribution channels are point-symmetrical with respect to the central axis and / or axially symmetrical with respect to a radial axis perpendicular to the central axis. Thus, the liquid distribution channel system is formed by a plurality of distribution channels, which expediently penetrate the holding device in such a way that the distribution channels are point-symmetrical with respect to the central axis and / or axially symmetrical with respect to the radial direction.

[0027] It can further be provided that the at least one distribution channel has a cross-sectional area, or that the distribution channels each have a cross-sectional area, wherein the cross-sectional area or the sum of these cross-sectional areas is smaller in area than a cross-sectional area of ​​the overflow opening of the rotor channel. This can ensure preferential cooling.

[0028] Furthermore, it is expediently provided that the holding device has support arms by means of which the holding device is fixed to a wall of the pump chamber. In particular, it can be provided that the holding device and the pump housing are designed integrally, for example as a cast, injection-molded, and / or transfer-molded component. Expediently, the support arms are each formed integrally with the said conical body of the holding device and / or the wall of the pump chamber. Furthermore, the support arms can be designed point-symmetrically with respect to the central axis and / or arranged point-symmetrically on the conical body with respect to the central axis.

[0029] Furthermore, it is advantageous for the support arms to have a flow-effective or flow-ineffective profile. This allows the flow rate to be specifically influenced as needed.

[0030] It is expediently provided that the hollow rotor axis has a plain bearing ring and the holding device has a counter-plain bearing ring, wherein the hollow rotor axis is supported axially and / or radially with respect to the central axis on the counter-plain bearing ring of the holding device via the plain bearing ring. The hollow rotor axis is thereby mounted on the holding device. It can expediently be provided that said receptacle of the holding device is designed in a stepped manner. In this case, the counter-plain bearing ring of the holding device can be arranged in a first step of the receptacle of the holding device that rests against said insertion opening of the receptacle of the holding device. Furthermore, the at least one distribution channel or the distribution channels of the liquid distribution channel system can open into the receptacle of the holding device at or in the region of a second step of the receptacle of the holding device that is adjacent to the first step.

[0031] In an alternative embodiment of the invention, it is expediently provided that the liquid distribution channel system is formed on or through the hollow rotor axis. The liquid distribution channel system can be realized by at least one distribution channel that passes through the hollow rotor axis and is configured to introduce the cooling flow from the rotor channel into the pump chamber in the inflow direction.

[0032] In a further alternative embodiment of the invention, it is expediently provided that the liquid distribution channel system is formed on or through the pump impeller. The liquid distribution channel system can expediently be formed by channels or chambers within the rotor channel and / or the pump impeller. This provides a further preferred embodiment of the electromotive pump, by means of which the cooling flow from the rotor channel can be introduced into the pump chamber in the inflow direction.

[0033] In summary, the present invention preferably relates to an electromotive pump for conveying a liquid, comprising a pump housing having an intake region and an outlet region and defining or forming a pump chamber. A hollow rotor shaft, through which a rotor channel passes, and a pump impeller rotatably mounted on the hollow rotor shaft for conveying liquid are arranged in the pump chamber. The electromotive pump has a cooling circuit open to the pump chamber, which is configured to cool an electric drive motor arranged in a motor region of the pump housing for rotating the pump impeller and / or control electronics.It is essential for the invention that the electromotive pump has a liquid distribution channel system which is designed to introduce a cooling flow of liquid flowing through the open cooling circuit during operation of the electromotive pump into the pump chamber in an inflow direction which is different from an axial direction which is parallel with respect to a central axis of the hollow rotor axis.

[0034] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

[0035] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0036] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein like reference numerals refer to like or similar or functionally identical components.

[0037] They show, schematically Fig. 1 is a longitudinal sectional view of a preferred embodiment of an electromotive pump according to the invention, Fig. 2 an excerpt from Fig. 1 according to a box marked there with a dashed line, Fig. 3 the electric motor pump Fig. 1, but in a different longitudinal section view, the section being taken through a support arm of the holding device, Fig. 4 a perspective view of the holding device of the electromotive pump from Fig. 1, Fig. 5 and Fig. 6 the holding device of the electromotive pump from Fig. 1 in a perspective view obliquely from behind, wherein in particular the rotor hollow axis and the rotor are shown in order to improve the visibility of the holding device.

[0038] The Fig. 1 to 6 show a preferred embodiment of an electromotive pump according to the invention, designated overall by reference numeral 1, by means of which any liquids, such as water and the like, can be pumped reliably and with predeterminable volume flows. For example, this can be an electromotive cooling pump for a vehicle that can be used in automotive engineering, although the field of application of the proposed electromotive pump 1 is not limited to this.

[0039] The electromotive pump 1 according to Fig. 1 has, purely by way of example, a multi-part pump housing 2, which has at least one intake region 3 with two separate inlets 51, 52, an outlet region 4, an upper housing part 46, and a lower housing part 47 arranged on the upper housing part 46. The upper housing part 46 of the pump housing 2 delimits or forms a pump chamber 5, into which the intake region 3 and the outlet region 4 open. A first path 7, indicated by a dashed line, for a delivery flow 8 of liquid leads through the intake region 3, the pump chamber 5, and the outlet region 4, wherein the liquid can flow through the intake region 3, the pump chamber 5, and the outlet region 4 in this order. Fig. 1 further shows that an axial section of a hollow rotor axis 11, through which a rotor channel 10 passes axially, and a pump impeller 12, which is rotatably adjustable on the hollow rotor axis 11 about the central axis 9 and driven by an electric motor, for conveying liquid are arranged in the pump chamber 5. The pump impeller 12 is designed here as a radial pump impeller and divides the pump chamber 5 into a high-pressure section 25 and a low-pressure section 24, with the high-pressure section 25 being arranged between an outflow side 48 of the pump impeller 12 and the outlet region 4, and the low-pressure section 24 being arranged between an inflow side 30 of the pump impeller 12 and the intake region 3. In terms of fluid mechanics, a compression section 26, in which the pump impeller 12 is located, is arranged between the low-pressure section 24 and the high-pressure section 14.The hollow rotor axis 11 has an axial end face 27 on its said axis section arranged in the pump chamber 5, at which the rotor channel 10 opens out to form an overflow opening 28.

[0040] The lower housing section 47 of the pump housing 2 delimits or forms a motor area 6 arranged on the pump chamber 5, in which an electric drive motor 18 is arranged for rotating the pump impeller 12. Electronic components, designated here in their entirety by 49, for controlling the electric drive motor 18 are placed in the motor area 6. The hollow rotor shaft 11 has, on its further axial section, a counter-axial end face 35 facing away from the pump chamber 5 and the axial end face 27 of the hollow rotor shaft 11, arranged in the motor area 6, at which the rotor channel 10 opens to form an inlet opening 36.Furthermore, it can be seen that a supply connection 50 is arranged on the lower housing part 47, via which the electric drive motor 18 and the electronic components 49 are supplied with electrical energy and information can be exchanged, for example, with an external control unit not illustrated here. The upper housing part 46 and the lower housing part 47 are fixed to one another in a fluid-tight and releasable manner, for example, using fastening screws and sealing means such as sealing cords or the like.

[0041] During proper operation of the electromotive pump 1, the electric drive motor 18 and the electronic components 49 heat up. The electromotive pump 1 is therefore equipped with a cooling circuit 13 open to the pump chamber 5 or the flow rate 8, by means of which the electric drive motor 18 and / or the electronic components 49 can be cooled and kept within a specified operating temperature range.

[0042] The open cooling circuit 13 is formed by the rotor channel 10, a bypass channel 14 that fluidically connects the pump chamber 5 to the rotor channel 10, and a fluid distribution channel system 15 that fluidically connects the rotor channel 10 to the pump chamber 5. In the present case, the bypass channel 14 extends at least partially through the housing bottom part 47 of the pump housing 2 and / or at least partially through the motor area 6. A second path 16 for a cooling flow 17 of liquid extends through the open cooling circuit 13. During operation of the electromotive pump 1, liquid branched off from the pump chamber 5 at an inlet 53 of the open cooling circuit 13 can initially flow into the bypass channel 14 as cooling flow 17. The cooling flow 17 then flows completely through the bypass channel 14 and enters the rotor channel 10 via the inlet opening 36.The cooling flow 17 flows completely through the rotor channel 10 and enters the liquid distribution channel system 15 via the overflow opening 28, so that the cooling flow 17 is then returned to the pump chamber 5 via the liquid distribution channel system 15 at an outlet 54 of the open cooling circuit 13. Along the second path 16, the cooling flow 17 absorbs heat from the components of the electromotive pump 1 to be cooled, which is then conducted into the pump chamber 5 with the cooling flow 17 and discharged from the electromotive pump 1 with the delivery flow 8. 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 distribution channel system 15 by means of a pressure difference established between the inlet 53 and the outlet 54.For this purpose, the outlet 54 is arranged in the delivery flow 8 upstream of the inlet 53, for example in the low-pressure section 24 or in the compression section 25 of the pump chamber 5.

[0043] The said liquid distribution channel system 15 is configured in the present case to introduce the cooling flow 17, which flows through the open cooling circuit 13 during operation of the electromotive pump 1, into the pump chamber 5 with a predetermined inflow direction 19. The inflow direction 19 differs from an axial direction 20 parallel to the center axis, i.e., an axial direction 20 aligned parallel to the center axis 9. The inflow direction 19 preferably runs radially with respect to the center axis 9 and can, in particular, be perpendicular to the center axis 9. More preferably, the inflow direction 19 runs parallel or substantially parallel with respect to the flow direction 22 of the delivery flow 8, which is established during operation of the electromotive pump 1 in an inflow region 23 of the pump chamber 5 into which the cooling flow 17 is introduced.Based on the orientation of the inflow direction 19, the cooling flow 17 is introduced into the pump chamber 5 such that it encounters the flow 8 at a more fluidically favorable angle than before. This reduces undesirable fluid mechanical effects such as turbulence or the like, thus reducing the flow resistance of the electromotive pump 1 and achieving a comparatively high hydraulic efficiency.

[0044] In Fig. 1-6, it can be seen that in the low-pressure section 24 of the pump chamber 5, a holding device 29 for the hollow rotor shaft 11 is arranged, which is opposite the inflow side 30 of the pump impeller 12 facing the intake area 3 and has a receptacle 31 in which the hollow rotor shaft 11 is received together with its overflow opening 28. The holding device 29 has or is formed by a conical body 37 arranged coaxially with respect to the central axis 9. The conical body has a conical tip 38, which faces the intake area 3, and a conical bottom 55, at which the receptacle 31 of the holding device 29 opens out, forming an insertion opening 39 for the hollow rotor shaft 11. Furthermore, in the Fig. 1-6 that the holding device 29 is fixed to a wall 41 of the upper housing part 46 by means of three integral support arms 40. The said receptacle 31 is in this case stepped and has a first step 44 adjacent to the said insertion opening 39 of the receptacle 31, in which a counter plain bearing ring 43 is received and fixed. The pump impeller 12 has a plain bearing ring 42, wherein the pump impeller 12 is supported via the plain bearing ring 42 axially and / or radially with respect to the center axis 9 on the counter plain bearing ring 43 of the holding device 29 and / or on the hollow rotor shaft 11. The holding device 29 in this case has a plurality of distribution channels 32a, 32b, 32c, which together form the said liquid distribution channel system 15. The distribution channels 32a, 32b, 32c pass through the holding device 29 orthe conical body 37 of the holding device 29 in the inflow direction 19, starting from the first step 44, from an inner surface 33 of the receptacle 31 of the holding device 29 to a lateral surface 34 of the holding device 29 facing the pump chamber 5, whereby they can introduce the cooling flow 17 from the rotor channel 10 in the inflow direction 19 into the pump chamber 5. In . Fig. 5 and Fig. 6 it can be seen that the distribution channels 32a, 32b, 32c are point-symmetrical with respect to the central axis 9 and / or axially symmetrical with respect to a radial direction perpendicular to the central axis 9. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 073 119 A1

[0003] US 2017 / 0268523 A1

[0003]

Claims

[1] Electromotive pump (1) for pumping a liquid, in particular an electromotive cooling pump for a vehicle, - with a pump housing (2) which has a suction area (3) and an outlet area (4) and which delimits or forms a pump chamber (5) into which the suction area (3) and the outlet area (4) open, - wherein a first path (7) for a flow (8) of liquid leads through the suction area (3), the pump chamber (5) and the outlet area (4), so that the suction area (3), the pump chamber (5) and the outlet area (4) can be flowed through by liquid, - wherein a hollow rotor shaft (11) defining a central axis (9) and axially penetrated by a rotor channel (10) and a pump impeller (12) mounted on the hollow rotor shaft (11), rotatably adjustable about the central axis (9) and driven by an electric motor are arranged in the pump chamber (5) for conveying liquid, - wherein the electromotive pump (1) has a cooling circuit (13) open to the pump chamber (5), which is formed by the rotor channel (10), a bypass channel (14) which fluidically connects the pump chamber (5) to the rotor channel (10), and a liquid distribution channel system (15) which fluidically connects the rotor channel (10) to the pump chamber (5), - wherein a second path (16) for a cooling flow (17) of liquid leads through the open cooling circuit (13), so that the bypass channel (14) and the rotor channel (10) can be flowed through by liquid for the purpose of cooling an electric drive motor (18) arranged in a motor area (6) of the pump housing (2) for rotating the pump impeller (12) as well as the liquid distribution channel system (15), - wherein the liquid distribution channel system (15) is designed to introduce a cooling flow (17) consisting of liquid branched off from the delivery flow (8), which flow through the open cooling circuit (13) during operation of the electromotive pump (1), into the pump chamber (5) in an inflow direction (19) which is different from an axial direction (20) parallel to the center axis. [2] Electromotive pump (1) according to claim 1, characterized by , that - the inflow direction (19) is radial with respect to the central axis (9). [3] Electromotive pump (1) according to claim 1 or 2, characterized by , that - the inflow direction (19) runs perpendicular to a flow direction of the cooling flow (17) within the rotor channel (10). [4] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the inflow direction (19) is aligned parallel or substantially parallel with respect to a flow direction (22) of the conveying flow (8). [5] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the liquid distribution channel system (15) is arranged to introduce the cooling flow (17) into a low-pressure section (24) of the pump chamber (5), which is arranged axially between the inflow side (30) of the pump impeller (12) and the suction region (3). [6] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the rotor channel (10) opens out at an axial end face (27) of the hollow rotor axis (11) arranged in the pump chamber (5) to form an overflow opening (28), - wherein a holding device (29) for the hollow rotor shaft (11) is arranged in the pump chamber (5), which holding device is opposite an inflow side (30) of the pump impeller (12) facing the intake area (3) and has 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 distribution channel (32a, 32b, 32c) which forms the liquid distribution channel system (15). [7] Electromotive pump (1) according to claim 6, characterized by , that - the at least one distribution channel (32a, 32b, 32c) passes through the holding device (29) in the inflow direction (19) starting from an inner surface (33) of the receptacle (31) of the holding device (29) up to a lateral surface (34) of the holding device (29) facing the pump chamber (5). [8] Electromotive pump (1) according to claim 6 or 7, characterized by , that - at least one further distribution channel (32a, 32b, 32c) is provided, - wherein the distribution channels (32a,32b,32c) are point-symmetrical with respect to the central axis (9). [9] Electromotive pump (1) according to one of claims 6 to 8, characterized by , that - the holding device (29) has support arms (40) by means of which the holding device (29) is fixed to a wall (41) of the pump chamber (5). [10] Electromotive pump (1) according to claim 9, characterized by , that - the support arms (40) have a flow-effective or flow-ineffective profile. [11] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the liquid distribution channel system (15) is formed on or through the hollow rotor axis (11). [12] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the liquid distribution channel system (15) is formed on or through the pump impeller (12). [13] Electromotive pump (1) according to one of the preceding claims, characterized by , that - the pump impeller (12) has a plain bearing ring (42) and the holding device (29) has a counter plain bearing ring (43), - wherein the pump impeller (12) is supported axially and / or radially with respect to the central axis (9) via the plain bearing ring (42) on the counter plain bearing ring (43) of the holding device (29) and / or the hollow rotor axis (11).

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