Pump unit with cooled drive

Abstract

The present invention relates to a pump unit for transporting a liquid, having a drive side, comprising a control unit and a drive unit, having a stator, a rotor and a drive shaft, which are arranged in a drive housing, and a pump side having a pump impeller and a pump housing. Here, the drive shaft is configured to drive the pump impeller in rotation about an axis of rotation, wherein the drive housing encloses the drive unit on a circumferential side and a first axial region with respect to the axis of rotation. The first axial region separates the drive side from the pump side, wherein the control unit is arranged on the drive housing between the drive unit and the pump side.

Description

[0001] Description

[0002] title drive

[0003] State of the art

[0004] The present invention relates to a pump unit for transporting a liquid.

[0005] When developing new pump units consisting of a pump and a pump drive, higher performance requirements are often placed on the product while maintaining a constant size. Current designs passively cool a pump control unit, with the heat flow from the control unit being dissipated to the environment through thermal paste and a housing. This passive cooling concept carries a high risk of insufficient cooling performance without sufficient ambient airflow. Furthermore, state-of-the-art pump drives often use containment shells between a rotor and a stator, resulting in performance degradation due to the increased distance between the rotor and stator.

[0006] It would be desirable to have a pump unit with better thermal management and higher power density. In particular, with simple and cost-effective active cooling of the control unit and the drive unit, as well as a reduced gap between the rotor and stator of the drive unit.

[0007] Disclosure of the invention

[0008] The pump unit according to the invention for transporting a liquid with the features of claim 1 has the advantage that the drive unit is free of a containment shell and thus the gap between the rotor and stator can be reduced. Furthermore, the control unit of the pump unit is actively cooled by a liquid which the pump unit transports. This makes it possible to increase the power density of the pump unit while being simple and cost-effective to manufacture. This is achieved according to the invention in that the pump unit has a drive side and a pump side. The pump unit comprises an impeller and a pump housing. The drive side comprises a control unit and a drive unit with a stator, a rotor and a drive shaft, which are arranged in a drive housing. The drive shaft is designed to drive the impeller in rotation about a rotational axis.The drive housing encloses the drive unit on a circumferential side and a first axial region relative to the rotational axis, with the first axial region of the drive housing separating the drive side from the pump side. The control unit is arranged between the drive unit and the pump side on the drive housing. In particular, the control unit is arranged flush with the first axial region of the drive housing. The control unit is thus arranged directly on the drive housing on the pump side, whereby the control unit can be actively cooled by the fluid in the pump unit. Furthermore, waste heat from the drive unit can be effectively dissipated via the drive housing, which is adjacent to the pump side. Heat dissipation from the control unit can be increased by applying thermal paste between the control unit and the drive housing.Preferably, the drive housing is configured to be contacted by a fluid on the pump side, in particular at the first axial region of the drive housing. The pump is preferably a flow pump, in particular an axial pump or a radial pump.

[0009] The subclaims show preferred developments of the invention.

[0010] Preferably, the pump unit comprises a cover which closes the drive side on a second axial region facing away from the pump side.

[0011] More preferably, the stator lies radially flush with the drive housing. This allows heat from the stator to be dissipated directly to the drive housing and does not build up in the drive unit. Particularly preferably, the drive housing has a cooling structure which is cooled with fluid from the pump side. The cooling structure enables improved heat dissipation from the drive housing, so that the performance of the pump unit can be increased. The cooling structure preferably has a cooling inlet and a cooling outlet which are in communication with the fluid on the pump side. The fluid at the fluid inlet preferably has a higher pressure than at the fluid outlet. This allows the fluid to move through the cooling structure without additional drive units and enables efficient cooling of the drive side.

[0012] Preferably, the drive housing has straight cooling channels that run parallel to the rotational axis, with deflection channels arranged in the pump housing and / or the cover to distribute the fluid between the cooling channels. Thus, the cooling channels can form a meandering structure. The separation into straight cooling channels in the drive housing and deflection channels in the pump housing and the cover enables easy manufacture of a complex cooling structure. The drive housing can thus be manufactured, for example, by casting and / or machining.

[0013] Further preferably, a cooling sleeve is arranged radially to the rotational axis, between the cover and the drive housing, which is configured to cool the drive side using the fluid from the pump side. The cooling sleeve enables efficient cooling of the drive side. Furthermore, the cooling sleeve can be easily and cost-effectively integrated between the cover and the drive housing.

[0014] A turbulator is preferably installed in the cooling sleeve. The turbulator promotes turbulent flow within the cooling sleeve. This results in increased mixing of the fluid within the cooling sleeve and thus in better heat dissipation from the drive side.

[0015] Further preferably, a cooling fin structure is arranged in the cooling sleeve. The cooling fins can increase the heat transfer surface in the cooling sleeve and guide the fluid in a targeted manner to improve heat dissipation through the cooling sleeve. The cooling fin structure is preferably helical. This allows the fluid in the cooling sleeve to be guided radially around the drive side and cool evenly around the circumference.

[0016] More preferably, the cooling fin structure has a straight structure that extends parallel to the rotation axis. This enables particularly uniform cooling in the axial direction with low pressure loss.

[0017] Preferably, the drive shaft extends through the drive housing. This allows a pump impeller on the pump side to be driven directly by the drive shaft. The drive shaft is preferably mounted in the drive housing.

[0018] Further preferably, a shaft seal is mounted between the drive shaft and the drive housing. The shaft seal can ensure a reliable seal between the pump side and the drive side, so that no fluid from the pump side passes through the area between the drive shaft and the drive housing to the drive unit or the control unit.

[0019] The drive shaft is preferably mounted in the cover. This ensures a compact design of the pump unit.

[0020] Short description of the drawings

[0021] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing:

[0022] Figure 1 is a schematic sectional view of a pump unit according to a first embodiment of the invention,

[0023] Figure 2 is a schematic sectional view of the pump unit according to a second embodiment of the invention,

[0024] Figure 3 is a perspective view of a cooling structure of the

[0025] Pump unit according to the second embodiment of the invention, Figure 4 is a schematic first sectional view of the pump unit according to a third embodiment of the invention,

[0026] Figure 5 is a schematic second sectional view of the pump unit according to the third embodiment of the invention and

[0027] Figure 6 is a perspective view of a cover of a

[0028] Pump unit according to a fourth embodiment of the invention.

[0029] Embodiments of the invention

[0030] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0031] A pump unit 1 for transporting a liquid 2 is described in detail below in Figures 1 to 6.

[0032] Figure 1 shows the pump unit 1, which comprises a drive side 10 and a pump side 40.

[0033] The drive side 10 has a control unit 3 and a drive unit 20, which are arranged in a drive housing 12. The drive unit 20 is an electric drive consisting of a stator 21 and a rotor 22 arranged therein, which sits on a drive shaft 23. The stator 21 is configured to drive the rotor 22 and the drive shaft 23 in rotation about a rotation axis XX.

[0034] The control unit 3 preferably comprises power electronics, in particular an electrical converter, to control the drive unit 20.

[0035] The drive housing 12 encloses the drive unit 10 on a circumferential side 25 and in a first axial region 26. The first axial region 26 separates the drive side 10 from the pump side 40, so that the outer side of the drive housing 12 is configured at the first axial region 26 to contact the liquid 2 on the pump side 40.

[0036] On a second axial region 27 facing away from the pump side 40, a cover 14 closes the drive side 10. The cover 14 contacts the drive housing 12, with a seal 4 arranged between the drive housing 12 and the cover 14. Thus, the drive unit 20 is completely sealed from the outside by the drive housing 12 and the cover 14.

[0037] The control unit 3 is attached to the first axial region 26 on the inside of the drive housing 12 using a thermally conductive paste 31. Thus, the waste heat from the control unit 3 can be dissipated directly to the fluid 2 on the pump side 40 via the first axial region 26 of the drive housing 12. The control unit 3 is connected to the stator 21 via electrical lines and is configured to control the pump unit 1.

[0038] The stator 21 lies flush with the drive housing 12 on the circumference, so that the heat of the stator 21 can be dissipated directly via the drive housing 12 on the circumference to the environment and via the first axial region 26 to the liquid 2.

[0039] The pump side 40 is designed as an axial pump and comprises a pump impeller 41 and a pump housing 42. The pump impeller 41 is directly connected to the drive shaft 23 and is driven in rotation by the drive shaft 23. The fluid 2 flows axially through an inlet 43 into the pump side 40, where it is accelerated by the pump impeller 41 and exits the pump side 40 radially toward the rotation axis XX through an outlet 44. The inlet 43 is arranged coaxially to the rotation axis XX. The outlet 44 is arranged perpendicular to the rotation axis XX.

[0040] To drive the pump impeller 41 using the drive shaft 23, the drive shaft 23 is guided through the drive housing 12 at the first axial region 26. A shaft seal 24, preferably designed as a radial shaft seal, is mounted between the drive shaft 23 and the drive housing 12. The shaft seal 24 prevents the fluid 2 from penetrating from the pump side 40 into the drive side 10. Furthermore, the drive shaft 23 can be mounted in the drive housing 12, for example, by means of a rolling bearing.

[0041] A further seal 4 is arranged between the pump housing 42 and the drive housing 12 in order to prevent leakage of liquid 2 between the pump housing 42 and the drive housing 12.

[0042] The pump housing 42, the drive housing 12 and the cover 14 are preferably aluminum components, which have high thermal conductivity while being lightweight.

[0043] Figure 2 schematically shows the pump unit 1 according to a second embodiment of the invention. The second embodiment differs from the first embodiment in particular by an additional cooling structure 16. The cooling structure 16 is arranged in the pump housing 42, the drive housing 12, and the cover 14. Thus, the heat dissipation of the drive side 10 can be increased and the power density of the pump unit 1 can be increased.

[0044] The cooling structure 16 diverts fluid 2 from the pump side 40 to cool the drive side 10. For this purpose, a cooling inlet 28 is arranged in the pump housing 42, into which the fluid 2 for the cooling structure 16 flows. After the fluid 2 has flowed through the cooling structure 16, the fluid 2 is fed again to the pump side 40 through a cooling outlet 29. The pressure at the cooling inlet 28 is higher than at the cooling outlet 29, so that the fluid 2 flows independently through the cooling structure 16 due to the pressure gradient.

[0045] Straight cooling channels 17 are arranged in the drive housing 12, with the fluid 2 being redirected between the cooling channels 17 by means of deflection channels 19. The deflection channels 19 are arranged both in the pump housing 42 and in the cover 14.

[0046] Figure 3 shows a perspective view of the cooling structure 16 in the pump housing 42, the drive housing 12, and the cover 14. The cooling structure 16 has a meandering shape that extends circumferentially around the rotation axis XX. Straight cooling channels 17 with a flat cross-section are arranged in the drive housing 12, with the width of the cooling channels 17 being significantly greater than their height. Preferably, the cross-section of the cooling channels 17 is curved circumferentially and thus adapted to a radius of the drive housing 12.

[0047] In the cover 14 and the pump housing 42, the deflection channels 19 are arranged alternately around the circumference to redirect the liquid 2 from one cooling channel 17 to the next cooling channel 17. The deflection channels 19 have a semi-annular shape.

[0048] Furthermore, Figure 3 shows a portion of the cooling inlet 28 and the cooling outlet 29. The cooling inlet 28 and the cooling outlet 29 are arranged on two adjacent cooling channels 17.

[0049] Figure 4 schematically shows a sectional view of the pump unit 1 according to a third embodiment, parallel to the rotation axis XX. The third embodiment differs from the second embodiment in particular in the design of the cooling structure 16.

[0050] In the third exemplary embodiment, the cooling structure 16 is designed as a cooling sleeve 13, which is arranged between the cover 14 and the drive housing 12. For this purpose, the cover 14 extends between the stator 21 and the drive housing 12 along the rotation axis XX, so that a cylindrical gap forms between the cover 14 and the drive housing 12, which forms the cooling sleeve 13.

[0051] The stator 21 lies flush with the circumferential side 25 of the cover 14 so that the waste heat of the stator 21 can be efficiently dissipated via the cover 14 and the cooling sleeve 13.

[0052] The third embodiment has one seal 4 between the pump housing 42 and the drive housing 12 and two seals 4 between the cover 14 and the drive housing 12. One seal 4 is arranged between the cover 14 and the drive housing 12 at the first axial region 26, and another seal 4 is arranged at the second axial region 27. Thus, the seals 4 prevent the liquid 2 from escaping from the cooling structure 16 to the environment or to the drive unit 20.

[0053] The cooling sleeve 13 also has a cooling inlet 28 and a cooling outlet 29, which branch off the liquid 2 from the pump side 40 to the cooling sleeve 13 and return it.

[0054] Figure 5 shows a schematic sectional view through the drive side 10 of the third embodiment perpendicular to the rotation axis XX.

[0055] The sectional view shows a cross-section through the cooling sleeve 13, in which a turbulator 15 is arranged. The turbulator 15 has a circumferentially wave-shaped cross-section with alternating bends. Thus, the turbulator 15 promotes mixing of the liquid 2, resulting in improved heat dissipation.

[0056] The cooling sleeve 13 has the cooling inlet 28 and the cooling outlet 29 on two opposite sides, so that the liquid 2 flows around the cooling sleeve on the circumference.

[0057] The stator 21 rests flush with the cover 14 on its circumference. The rotor 22 is arranged within the stator 21, separated by a thin gap. The rotor 22 encloses the drive shaft 23, which drives the impeller 41.

[0058] Figure 6 shows a perspective view of the cover 14 of the second axial region 27 according to a fourth embodiment. The fourth embodiment is similar to the third embodiment and differs in particular in the shape of the cooling structure 16.

[0059] The cover 14 in Figure 6 is configured to form the cooling sleeve 13 for the drive housing 12. A helical cooling fin structure 18 is arranged in the cooling sleeve 13.

[0060] The helical cooling fin structure 18 is part of the cover 14 and is configured to contact the drive housing 12 of the pump unit 1. Thus, the helical cooling fin structure 18 can guide the fluid 2 circumferentially around the rotation axis XX. The cooling fin structure 18 is preferably double-helix-shaped, allowing the fluid to flow along one strand in one direction and back along the other strand in an opposite direction.

[0061] The cooling sleeve 13 is delimited in the axial direction by two seals 4, which are designed to contact the drive housing 12. The fluid for the cooling sleeve 13 is preferably branched off from the pump side 40 and directed into the cooling sleeve 13 via the drive housing 12.

Claims

Claims 1. A pump unit for transporting a liquid (2), having a drive side (10) comprising a control unit (3) and a drive unit (20), having a stator (21), a rotor (22) and a drive shaft (23), which are arranged in a drive housing (12), and a pump side (40) having a pump wheel (41) and a pump housing (42), wherein the drive shaft (23) is configured to drive the pump wheel (41) in rotation about an axis of rotation (XX), wherein the drive housing (12) encloses the drive unit (10) on a circumferential side (25) and a first axial region (26) relative to the axis of rotation (XX), wherein the first axial region (26) separates the drive side (10) from the pump side (40), wherein the control unit (3) is arranged between the drive unit (20) and the pump side (40) on the drive housing (12).

2. Pump unit according to claim 1, comprising a cover (14) which closes the drive side (10) on a second axial region (27) facing away from the pump side (40).

3. Pump unit according to one of the preceding claims, wherein the stator (21) lies radially flush against the drive housing (12).

4. Pump unit according to one of the preceding claims, wherein the drive housing (12) has a cooling structure (16) which is cooled with liquid (2) of the pump side (40).

5. Pump unit according to claim 4, wherein the drive housing (12) has straight cooling channels (17) which run parallel to the rotation axis (XX), and wherein in the pump housing (42) and / or in the Cover (14) deflection channels (19) are arranged, which are designed to distribute the liquid (2) between the cooling channels (17).

6. Pump unit according to one of claims 2 to 5, wherein a cooling sleeve (13) is arranged radially to the axis of rotation (XX) between the cover (14) and the drive housing (12), which cooling sleeve is designed to cool the drive side (10) by means of the liquid (2) of the pump side (40).

7. Pump unit according to claim 6, wherein a turbulator (15) is arranged in the cooling sleeve (13).

8. Pump unit according to claim 6 or 7, wherein a cooling fin structure (18) is arranged in the cooling sleeve (13).

9. Pump unit according to claim 8, wherein the cooling fin structure (18) is helical.

10. Pump unit according to claim 8, wherein the cooling fin structure (18) has a straight structure which extends parallel to the axis of rotation (XX).

11. Pump unit according to one of the preceding claims, wherein the drive shaft (23) is guided through the drive housing (12).

12. Pump unit according to claim 11, wherein a shaft seal (24) is mounted between the drive shaft (23) and the drive housing (12).

13. Pump unit according to one of claims 2 to 12, wherein the drive shaft (23) is mounted in the cover (14).

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