EP4685354A1

EP4685354A1 - Pump device and method of assembly

Info

Publication number: EP4685354A1
Application number: EP24189990.5A
Authority: EP
Inventors: Cristinel Ionut Drula
Original assignee: Hella GmbH and Co KGaA
Current assignee: Hella GmbH and Co KGaA
Priority date: 2024-07-22
Filing date: 2024-07-22
Publication date: 2026-01-28
Also published as: CN121382653A

Abstract

Pump device (100) for a fluid circuit of a vehicle comprising at least a motor unit (1) with a stator (10) and a rotor (11) and an electronic control unit (12); and a housing unit (3) with a fluid chamber (30) with an inlet (E) and an outlet (A) and a dry chamber (31); wherein the stator (10) and the electronic control unit (12) are arranged in the dry chamber (31); and wherein the fluid chamber (30) comprises a rotor chamber (301) and an impeller chamber (302), which are connected to one another by an opening (303); and wherein the rotor (11) is arranged in the rotor chamber (301); and an impeller (2) for transmitting energy to a working fluid (F), wherein the impeller (2) is arranged in the impeller chamber (302) and is connected to the rotor (11) in a rotationally fixed manner. The rotor (11) is directly connected to the impeller (2) in a rotationally fixed manner, so that a circumferentially closed annular gap (R) results at the opening (303), whereby the working fluid (F) can enter the rotor chamber (301) for cooling the motor unit (1) and in particular the electronic control unit (12).

Description

The present invention relates to a pump device, in particular for a fluid circuit of a vehicle, for example a coolant pump, in which a working fluid, in particular a coolant, is also used to cool components of the pump device. The pump device comprises at least one motor unit with a stator and a rotor and an electronic control unit, an impeller for transferring energy to a working fluid, such as a coolant, a housing unit with a fluid chamber and a dry chamber, wherein the stator and the electronic control unit are arranged in the dry chamber and wherein the fluid chamber comprises a rotor chamber and an impeller chamber, which are connected by an opening. The rotor is arranged in the rotor chamber.
Various pump devices are known from the state of the art in which the working fluid is used to cool the motor unit and in particular the electronic control unit.
Especially pumps are known from the state of the art in which a separate channel is provided, which establishes a connection of an area at the outlet of the pump with the rotor chamber. Through the channel, part of the coolant can flow from the outlet side of the impeller, where it is under a higher pressure during operation than the coolant upstream of the impeller, into the rotor chamber and cool the rotor as well as the neighboring stator and the electronic control unit. The coolant flows past the rotor and is fed back into the impeller chamber through openings. The flow resistance is particularly high due to the narrow and long channel and the friction of the rotating rotor especially in between the small gap rotor and the wall of the rotor chamber. As a major disadvantage the motor unit can often be only insufficiently cooled. The power consumption of the pump device with a given motor unit is limited by the cooling capacity of the motor unit and, in particular, the electronic control unit. In practice, the risk of failure due to overheating of the motor unit components is a frequent cause of failure.
It is therefore the task of the present invention to provide an improved pump device which, in particular enables improved cooling of the motor unit, and preferably the electronic control unit. Furthermore, it is preferably the task of the present invention to provide a pump device which can be manufactured and assembled at low cost.
The problem is solved by a pump device with the features according to claim 1 and a method for assembling the pump device with the features according to claim 14. Preferred further embodiments are the subject of the subclaims. Further features and advantages result from the general description and from the description of the embodiments.
The pump device according to the invention, in particular for a fluid circuit of a vehicle, for example a coolant pump, comprises at least:

a motor unit, in particular an electric motor unit, with a stator and a rotor and an electronic control unit; and
a housing unit having a fluid chamber with an inlet and an outlet and a dry chamber; wherein the stator and the electronic control unit are arranged in the dry chamber; and
wherein the fluid chamber comprises a rotor chamber and an impeller chamber, which are connected to each other by an opening; and wherein the rotor is at least partially arranged in the rotor chamber; and
an impeller for transferring energy to a working fluid, such as a coolant, the impeller being arranged at least partially in the impeller chamber and connected to the rotor in a rotationally fixed manner.

The rotor is directly connected to the impeller in a rotationally fixed manner, in particular in a torsionally rigid manner, resulting in a circumferentially closed annular gap at the opening so that the working fluid can enter the rotor chamber for cooling the motor unit and in particular the electronic control unit.
The invention has many advantages. A significant advantage of the invention is that the working fluid can flow directly from the impeller chamber through the annular gap at the opening into the rotor chamber for cooling. No separate channels are required in the housing unit of the pump device to guide the working fluid from the outlet side of the impeller to the rotor chamber. As a result, the flow resistance is at least considerably lower here and a larger flow of volume of working fluid can result for the same given pressure difference, which can be led into the rotor chamber, compared to state of the art. This allows a higher potential of heat to be transported away from the motor unit, especially from the electronic control unit. Another advantage of the direct connection between the rotor and impeller is that the rotational movement of the rotor can be transmitted directly to the impeller so that no separate or incorporated shaft is required to transmit torque from the rotor to the impeller.
Preferably, the working fluid is located in the fluid chamber during intended use and there is no working fluid in the dry chamber. Advantageously, the fluid chamber and the dry chamber are separated from each other by at least one wall of the housing unit, so that no working fluid can enter the dry chamber from the fluid chamber. Preferably, the stator surrounds the rotor in an annular shape. In particular, the wall is arranged between the stator and the rotor.
In particular, a diameter of the opening is larger than a diameter of the rotor, so that the rotor can be inserted and mounted from the impeller chamber into the rotor chamber. Advantageously, the maximum diameter of the annular gap is therefore larger than the diameter of the rotor. The large diameter of the annular gap is particularly favorable for low flow resistance. It also makes an assembly considerably easier, as the rotor can simply be inserted into the opening from the side of the fluid chamber.
Preferably, an axle for supporting and/or centering the rotor, and in particular the impeller, is included. In particular, the axle is at least partially designed as a hollow axle through which the working fluid can flow back from the rotor chamber to the inlet side. Preferably, the rotor and/or the impeller are both rotatably mounted relative to the axle, preferably by one or more bearings. In particular the rotor and/or the impeller comprise a central continuous bore for mounting with the axle and/or the bearings. Advantageously, the axle is mounted on a wall of the rotor chamber of the housing unit, which is opposite to the opening. Advantageously, a mounting in which the axle is accommodated can be formed on the wall of the rotor chamber. Advantageously, the hollow shaft allows the working fluid to flow back directly to the inlet side of the impeller. Advantageously, the volume flow of the working fluid is driven by the maximum pressure difference present in the pump device. Furthermore, no additional channel is required in the housing unit to return the working fluid, as is the case with solutions known from the state of the art.
Particularly preferably, the fluid chamber comprises a cooling chamber, whereby the cooling chamber is connected to the rotor chamber, in particular directly, so that working fluid can flow from the rotor chamber into the cooling chamber and is directed through the cooling chamber and can flow back into the rotor chamber. Advantageously, the cooling chamber enables even better cooling of components of the motor unit, in particular the electronic control unit, in the dry chamber. Advantageously, the geometry of the cooling chamber can be predetermined so that the transfer of heat into the working fluid is optimized.
In particular, the cooling chamber is arranged at the end of the rotor chamber opposite to the opening, in particular adjacent to the electronic control unit. Preferably, the cooling chamber is located between the rotor chamber and the electronic control unit. Advantageously, this enables particularly effective cooling of the electronic control unit. Preferably, the electronic control unit is arranged directly on a wall of the cooling chamber and is advantageously connected to the wall of the cooling chamber in at least a thermally conductive manner, e.g. by means of a transfer element such as a thermally conductive paste.
The cooling chamber is preferably connected to the rotor chamber by several connecting bores. Advantageously, the connecting bores allow the working fluid to flow into the cooling chamber and out again. Preferably, the working fluid can exit the rotor chamber through a central connection bore, close to an axis of rotation of the rotor, and in particular enter the cooling chamber through decentralized connection bores. This advantageously enables a flow, particularly in a central direction. In particular, the central connecting bore can be arranged in such a way that the working fluid can be led directly into a hollow axle. Advantageously, the working fluid then flows from the rotor chamber into the cooling chamber and then into the hollow axle, which is arranged in the rotor chamber.
Preferably, the cooling chamber is comprised of a cooling unit, which comprises at least one circumferential wall and a cover and/or a base.
In particular, the cooling unit is at least partially enclosed by the housing unit. Preferably, the cooling unit is at least partially made of the same material as the housing unit, in particular plastic. In an advantageous further embodiment, the wall of the cooling unit is formed by an extension of a wall of the rotor chamber of the housing unit. In particular, the extension is materially connected to the wall of the rotor chamber, preferably directly and/or indirectly. Advantageously, the extension can, for example, be molded directly during the manufacture of at least one part of the housing unit, for example by plastic injection molding. In particular the base is formed by the wall of the rotor chamber.
Alternatively, the cooling unit can also preferably be formed separately from the housing unit, whereby the cooling unit is then arranged next to the rotor chamber and in particular connected to the rotor chamber, preferably in a flow-conducting manner. In this case, the cooling unit comprises at least one material with high thermal conductivity, in particular a metal, such as copper or aluminum to enhance heat transfer. Advantageously at least the base of the cooling unit is overmolded during injection molding of the wall of the housing unit.
In particular, the cover is directly connected to the wall of the housing unit by a material connection. Preferably, a material connection is produced by welding, in particular by friction welding. In a process for joining the wall and the cover, a welding process and in particular a friction welding process is preferably used. Advantageously, the friction welding process is particularly economical, as the connection is made solely by localized melting of the joining partners. In addition, the connection is advantageously robust and resilient. Alternatively, the material connection is produced by soldering, e. g. when the cooling unit is separate. Furthermore, other methods such as bonding or the like can also be used to create the connection.
Preferably, the cooling unit comprises at least one transmission element for improving heat transfer into the working fluid within the cooling chamber. Preferably, the transfer element comprises a heat conducting paste and/or a heat conducting plate and/or a heat conducting pad or the like. In particular, this further improves heat conduction from the electronic control unit into the working fluid. Advantageously, a transfer element can also be designed as a collar, in particular a one-piece collar, on the cover.
Preferably, the pump device is designed as a radial centrifugal pump. In a centrifugal pump, the electronic control unit is advantageously arranged on an opposite side of the rotor to the impeller, so that the invention can be used particularly effectively here. In addition, the pump device can also be designed as a diagonal centrifugal pump or as an axial pump.
Further advantageous embodiments and properties of the pump device described above can be seen from the overall general description and from the description of the embodiments.
In the method according to the invention for assembling a pump device described above, a rotor assembly is first assembled, wherein the rotor assembly comprises at least the rotor and the impeller, and the rotor and the impeller are connected to each other directly and in a rotationally fixed manner. The rotor assembly is then at least partially inserted into the rotor chamber of the housing unit through the opening. In particular at least a part of the rotor is inserted into the rotor chamber. The rotor assembly can also comprise an axle, in particular a hollow axle and one or more bearings. Preferably, the axle and/or bearings are also mounted before the rotor assembly is at least partially inserted into the fluid chamber. In particular, the rotor is inserted into the rotor chamber through the opening. Further components and process steps may be included in the assembly.
The method according to the invention also has also many advantages. A significant advantage of the method is that the rotor assembly can be pre-assembled and then inserted into the housing unit in a single work step. It is not necessary to mount the impeller on a shaft. Further features and advantages of the method can be seen from the overall general description and from the description of the embodiments.
Further features and advantages of the embodiments of the invention are described below with reference to the drawings. The same reference signs are used for identical or similar parts and for parts with identical or similar functions. It shows:

Fig. 1: a schematic sectional view of an embodiment of a pump device according to the invention;
Fig. 2: a schematic exploded view of a pump device according to the invention;
Fig. 3: a schematic sectional view of another embodiment of a pump device according to the invention with a separate cooling unit; and
Fig. 4: schematic sectional view of a separate cooling unit.

It is not necessary for a pump device according to the invention and/or a method according to the invention to have all of the features described below. It is also possible for a pump device according to the invention and/or a method according to the invention to have only individual features of the embodiments described below.
Fig. 1 shows a schematic sectional view of an embodiment of a pump device 100 according to the invention. The pump device 100 is designed here as a radial centrifugal coolant pump for a fluid circuit of a vehicle. The pump device 100 comprises a motor unit 1 with a stator 10 and a rotor 11 and an electronic control unit 12. There is an impeller 2 for transmitting energy to a working fluid F, here a coolant F, wherein the impeller 2 is connected to the rotor 11 in a rotationally fixed manner. There is a housing unit 3 with a fluid chamber 30 with an inlet E and an outlet A and a dry chamber 31. The stator 10 and the electronic control unit 12 are arranged in the dry chamber 31. The fluid chamber 30 comprises a rotor chamber 301 and an impeller chamber 302, which are connected by an opening 303. The rotor 11 can be inserted and mounted in the rotor chamber 301 through the opening 303 of the impeller chamber 302. For this purpose, a diameter 3031 of the opening 303 is larger than a diameter 1101 of the rotor 11. The rotor 11 is directly connected to the impeller 2 in a rotationally fixed manner, resulting in a circumferentially closed annular gap R at the opening 303, into which the working fluid F can enter the rotor chamber 301 for cooling the motor unit 1 and, in particular the electronic control unit 12. A flow resistance at the annular gap R is low, so that the working fluid F can enter from the outlet side of the impeller 2 from the impeller chamber 302 through the opening 303 into the rotor chamber 301 for cooling the motor unit 1.
A central axle 13 is present here, which is designed here as a hollow axle 13. The rotor 11 is held here by bearings 14 on the hollow axle 13 with the impeller 2. The working fluid F can be led back through the hollow axle 13 from the rotor chamber 301 into an inlet area in front of the impeller 2 back into the impeller chamber 302, where the pressure is particularly low. As a result, the greatest possible pressure difference is here utilized to drive the flow for cooling the motor unit 1. Advantageously, a separate channel through the housing unit 2 is no longer necessary compared to state of the art.
The hollow axle 13 with the bearings 14 as well as the rotor 11 and the impeller 2 form a rotor assembly RB, which can be mounted without the housing unit 2 and can then be inserted into the housing unit as a mounted rotor assembly through the opening 303. This also enables cost-effective assembly.
At the opposite end of the rotor chamber 301 to the opening 303, there is a cooling chamber 40 of a cooling unit 4. The cooling chamber 40 is connected here to the rotor chamber 301 by connecting bores 401, so that the working fluid F can flow from the rotor chamber 301 into the cooling chamber 40 and trough the cooling chamber 40 and back into the rotor chamber 301. Here, the working fluid F flows through decentralized connection bores 401 into the cooling chamber 40 and through a central connection bore 401 back out of the cooling chamber 40 and here directly into the hollow shaft 13 in the rotor chamber 301 and then back into the impeller chamber 302 in front of the impeller 2.
The cooling chamber 40 is arranged here between the rotor chamber 301 and the electronic control unit 12. As a result, a high amount of heat can be transferred from the electronic control unit 12 so that overheating can be prevented much better during operation. Furthermore, a transfer element 41 in the form of a heat conducting pad is provided in order to optimize the heat conduction to the cooling chamber 40. The geometric dimensions of the cooling chamber 40 are advantageously designed here in such a way that heat transfer into the working fluid F is optimized.
The cooling unit 4 here comprises a wall 402 and a cover 403. A base 404 is formed by the wall 32 of the rotor chamber 301 of the housing unit 3. The wall 402 is formed here as an extension 321 of the wall of the housing unit 3. Here, the wall 32 of the rotor chamber 301 and the extension 321 are both made of a plastic in an injection molding process. The cover 403 is then joined to the wall 402 by friction welding. This makes production particularly cost-effective.
Fig. 2 shows a schematic exploded view of the pump device 100 according to the invention as shown in Fig. 1
Fig. 3 shows a schematic sectional view of a further embodiment of a pump device 100 according to the invention. Here, the cooling unit 4 is formed separately and made of a metal, in this case aluminum. This allows the heat transfer into the working fluid F to be further improved. The rotor chamber 301 is connected here to the housing unit 3 in a flow-conducting manner and also comprises a cover 403 and a wall 402 and a base 404, wherein the cover 403 and the wall 402 are connected to each other by soldering. Furthermore, positioning pins 405 are provided for correct positioning of the cover 402 and the base 404 to each other.
For manufacturing the base 404 is first inserted into a mold and overmolded in plastic injection molding process for forming the housing unit 3. Afterwards the cover 402 is assembled and connected by soldering.
Fig. 4 shows a schematic sectional view of the separate cooling unit 4 according to Fig. 3.

Reference symbols

1: motor unit
10: stator
11: rotor
1101: diameter of the rotor
12: control unit
13: axle, hollow axle
14: bearing
2: impeller
3: housing unit
30: fluid chamber
301: rotor chamber
302: impeller chamber
303: opening
3031: diameter of the opening
31: Dry chamber
32: wall of the housing unit
321: extension of the wall
4: cooling unit
40: cooling chamber
401: connecting bore
402: wall of the cooling chamber
403: cover of the cooling unit
404: base of the cooling unit
405: positioning pin
41: transmission element
100: pump device
E: inlet
F: fluid, coolant
A: outlet
R: annular gap
RB: rotor assembly

Claims

Pump device (100) in particular for a fluid circuit of a vehicle, for example a coolant pump (100), at least comprising:
- a motor unit (1) with a stator (10) and a rotor (11) and an electronic control unit (12); and

- a housing unit (3) with a fluid chamber (30) with an inlet (E) and an outlet (A) and a dry chamber (31); wherein the stator (10) and the electronic control unit (12) are arranged in the dry chamber (31); and

- wherein the fluid chamber (30) comprises a rotor chamber (301) and an impeller chamber (302), which are connected to each other by an opening (303); and wherein the rotor (11) is at least partially arranged in the rotor chamber (301); and

- an impeller (2) for transmitting energy to a working fluid (F), such as a coolant (F), wherein the impeller (2) is at least partially arranged in the impeller chamber (302) and is connected to the rotor (11) in a rotationally fixed manner;
characterized in that
the rotor (11) is directly connected to the impeller (2) in a rotationally fixed manner, so that a circumferentially closed annular gap (R) results at the opening (303) so that the working fluid (F) can enter the rotor chamber (301) for cooling the motor unit (1) and in particular the electronic control unit (12).
Pump device (100) according to claim 1, wherein a diameter (3031) of the opening (303) is larger than a diameter (1101) of the rotor (11), so that the rotor (11) can be inserted and mounted from the impeller chamber (302) into the rotor chamber (301).
Pump device (100) according to one of claims 1 or 2, comprising an axle (13) for supporting and/or centering the rotor (11), and in particular the impeller, wherein the axle (13) is at least partially formed as a hollow axle (13) through which the working fluid (F) can flow back from the rotor chamber (301) to the side of the inlet (E).
Pump device (100) according to the one of the preceding claims, wherein the fluid chamber (30) comprises a cooling chamber (40), wherein the cooling chamber (40) is connected to the rotor chamber (301), so that the working fluid (F) can flow from the rotor chamber (301) into the cooling chamber (40) and is directed through the cooling chamber (40) and can flow back into the rotor chamber (301).
Pump device (100) according to claim 4, wherein the cooling chamber (40) is arranged at the end of the rotor chamber (301) opposite to the opening (303), in particular adjacent to the electronic control unit (12).
Pump device (100) according to one of claims 4 or 5, wherein the cooling chamber (40) is arranged between the rotor chamber (301) and the electronic control unit (12).
Pump device (100) according to one of claims 4 to 6, wherein the cooling chamber (40) is connected to the rotor chamber (301) by a plurality of connecting bores (401).
Pump device (100) according to the preceding claim, wherein the working fluid (F) can exit through a central connecting bore (401) into the rotor chamber (301), and in particular can enter the cooling chamber (40) through decentral arranged connecting bores (401).
Pump device (100) according to one of claims 4 to 8, wherein the cooling chamber (40) is formed by a cooling unit (4), which comprises at least a circumferential wall (402) and a cover (403) and a base (404).
Pump device (100) according to the preceding claim, wherein the cooling unit (4) is at least partially enclosed by the housing unit (3); and wherein the wall (402) of the cooling unit (4) is formed by an extension (321) of the wall (32) of the rotor chamber (301) and the base (404) is formed by the wall (32) of the rotor chamber (301).
Pump device (100) according to claim 9, wherein the cooling unit is formed separately from the housing unit (3), whereby the cooling unit (4) is connected to the rotor chamber (301) in a flow-conducting manner.
Pump device (100) according to one of claims 9 to 11, wherein the cover (403) is connected to the wall (402) by a material bond, wherein the material connection is preferably produced by welding, in particular by friction welding, or by soldering.
Pump device (100) according to claim 11, wherein the cooling unit (4) comprises at least one material with high thermal conductivity, in particular a metal, such as copper or aluminum and/or wherein the cooling unit (4) is formed from the same material as the housing unit (3), in particular a plastic.
The pump device (100) according to one of claims 9 to 13, wherein the cooling unit (4) comprises a transfer element (41) for improving a heat transfer into the working fluid (F) within the cooling chamber (40).
A method of assembling a pump device (100) according to any one of the preceding claims,
- wherein a rotor assembly (RB) is mounted, which comprises at least the rotor (11) and the impeller (2), and wherein the rotor (11) and the impeller (2) are directly and non-rotatably connected to one another; and wherein

- at least a part of the rotor (11) of the rotor assembly (RB) is inserted into the rotor chamber (301) of the housing unit (3) through the opening (303).