ELECTRIC MACHINE WITH INTEGRATED HEAT EXCHANGER

Description

TECHNICAL FIELD

[0001] The invention relates to an electric machine, a geared motor with a gearbox and an electric machine coupled to the gearbox, and a vehicle driven by said electric machine or by said geared motor. STATE OF THE ART

[0002] Electrical machines are often part of complex technical systems or arrangements, which often have to be cooled at least in part in order to dissipate the waste heat generated in the various components of the technical systems or arrangements. Cooling circuits in which a liquid or gaseous heat transfer medium is used to transport the waste heat away are one possible solution. For example, the electrical machine can have at least one first coolant channel of a first cooling circuit through which a heat transfer medium flows. For example, a pump arranged in the first cooling circuit can transport the heat generated in the electrical machine with the help of the heat transfer medium to a heat exchanger, where the heat is released to the environment. The heat transfer medium can be a coolant, for example, and the heat exchanger a water-air heat exchanger.Not only the electric motor can have such a circuit, but also other devices contained in technical systems or arrangements. This means that, under certain circumstances, multiple cooling circuits with multiple heat exchangers must be installed in the technical systems or arrangements. Particularly when installation space is limited, the sensible arrangement of heat exchangers can become problematic. For example, radiators in vehicles are usually installed at the front of the vehicle, where installation space is naturally very limited.

[0003] The documents EP 3 028 888 A1, DE 10 2018 121203 A1, DE 10 2011 084033 A1, DE 10 2016 110658 A1, EP 2 020 735 A2, SU 951 566 A1 disclose electrical machines of the prior art. DISCLOSURE OF THE INVENTION

[0004] An object of the invention is therefore to provide an improved electric machine, an improved geared motor, and an improved vehicle with such an electric machine or such a geared motor. In particular, a possibility for cooling devices in technical systems or arrangements with limited available installation space is to be provided.

[0005] The object of the invention is achieved by an electrical machine which comprises a housing, a stator arranged in the housing and fixedly connected to the housing, and a rotor arranged in the housing, which is arranged on a rotor shaft and is rotatably mounted relative to the stator about the axis of rotation of the rotor and the rotor shaft. At least one first coolant channel of a first cooling circuit is arranged in the housing in the region of the stator. In addition, at least one second coolant channel of a second cooling circuit is arranged in the housing in the region of the stator, and the two coolant channels and the housing of the electrical machine form a heat exchanger between the first cooling circuit and the second cooling circuit. The at least one first coolant channel and the at least one second coolant channel are therefore not hydraulically connected to one another or are hydraulically separated from one another.

[0006] Furthermore, the object of the invention is achieved by a geared motor which comprises a transmission and an electric machine coupled to the transmission, wherein the transmission is hydraulically connected to the at least one second coolant channel of the second cooling circuit.

[0007] Finally, the object is also achieved by a vehicle having at least two axles, at least one of which is driven, said drive being effected at least partially or temporarily by the above-mentioned electric machine or the above-mentioned geared motor.

[0008] With the help of the proposed measures, the electric machine itself can function as a heat exchanger. The first cooling circuit cools the electric machine as such in a conventional manner. However, other devices to be cooled can also be connected to the electric machine. Heat generated in the external device to be cooled is transported to the electric machine via the heat transfer medium in the second cooling system and from there transferred to the first cooling system. From there, the heat is transported to a heat exchanger or cooler in the manner already described and there dissipated to the environment. This means that the external device to be cooled can also be cooled without the need for a separate heat exchanger. In this way, limited available space can be used optimally.

[0009] For example, the at least one first coolant channel can be cast into the housing of the electrical machine, and the at least one second coolant channel can be formed by a tube arranged in or adjacent to the at least one first coolant channel. In this way, existing first coolant channels can be used for the at least one second coolant channel, allowing existing electrical machines to be upgraded accordingly, or existing housings or housing shapes to be used for the construction of additional electrical machines.

[0010] However, it is also conceivable for the at least one first coolant channel and the at least one second coolant channel to be cast into the housing of the electric machine. This eliminates the need to arrange a pipe in the first coolant channel, simplifying the assembly of the electric machine.

[0011] In particular, the electric machine can have a sealing nipple that is hydraulically connected to the at least one second coolant channel and is designed for connecting a hose or pipe. In this way, the electric machine can be easily integrated into the second cooling circuit.

[0012] In particular, the at least one first coolant channel and the at least one second coolant channel can run helically. In principle, therefore, a single first coolant channel and a single second coolant channel can extend over the length of the electric machine. However, the at least one first coolant channel and the at least one second coolant channel can also run in a different direction. In particular, they can run - at least in sections - in the axial direction or along circles around the rotor axis. For example, a plurality of first coolant channels can also originate from a first collector and open into a second collector. Likewise, a plurality of second coolant channels can also originate from a first collector and open into a second collector.

[0013] At this point, it should be noted that the electric machine or other external device can be not only cooled but also heated using the proposed measures. For example, the drive motor and a transmission of a vehicle can be preheated using the proposed measures at low outside temperatures. Heat is transported in the opposite direction to cooling. A heater may be provided for this purpose in the first or second cooling circuit. The terms "cooling" and "heating" are therefore interchangeable within the scope of the disclosure. Further advantageous embodiments and developments of the invention emerge from the dependent claims and from the description in conjunction with the figures.

[0014] It is advantageous if two second coolant channels are provided for each first coolant channel, which belong to different cooling circuits or form sections of a single second cooling circuit with opposite flow directions. If the second coolant channels belong to different cooling systems, the number of second cooling systems can be doubled, whereby another device to be cooled can be cooled. This procedure is particularly advantageous if different heat transfer media are used or must be used in the two cooling systems and the devices to be cooled cannot be integrated into a second cooling system. If the second coolant channels form sections of a single second cooling system with opposite flow directions, then the heat-emitting surface in the second cooling system can be doubled, for example, and the cooling capacity can therefore also be almost doubled.For example, the two second coolant channels are connected to each other at one end.

[0015] It is furthermore advantageous if the rotor shaft is hollow and is hydraulically connected to the at least one second coolant channel of the second cooling circuit. In this way, the rotor of the electric machine can be cooled by the heat transfer medium in the second cooling system. In particular, the rotor shaft can also have cooling bores so that the heat transfer medium can reach the interior of the electric machine from the rotor shaft. In the case of a geared motor, it is also particularly advantageous if the rotor shaft is hollow and is hydraulically connected to the gearbox via a bearing arranged on the rotor shaft, and the rotor shaft and the bearing are part of the second cooling circuit. In this way, the gearbox can be cooled with the aid of the heat transfer medium in the second cooling system.

[0016] The above embodiments and further developments of the invention can be combined in any way. SHORT DESCRIPTION OF THE CHARACTERS

[0017] Embodiments of the invention are illustrated by way of example in the accompanying schematic figures. They show: Fig. 1 shows a schematic half-section of an exemplary electrical machine with a second coolant channel running in the first coolant channel; Fig. 2 shows a schematic example of the use of the heat exchanger integrated in the electrical machine; Fig. 3 shows a schematic half-section of an exemplary electrical machine with two second coolant channels running in the first coolant channel; Fig. 4 shows a similar Fig. 1 , but with a gearbox flanged to the electric machine; Fig. 5 a side view of the coolant channels of the electric machine according to Fig. 1 ; Fig. 6 a side view of the coolant channels of the electrical machine according to Fig. 3 ; Fig. 7 a side view of a first and second coolant channel cast into the housing; Fig. 8 a side view of a second coolant channel arranged in a groove of the housing; Fig. 9 similar to Fig. 5 , but with coolant channels extending in sections in the circumferential direction, Fig. 10 a first example of a sealing nipple; Fig. 11 a second example of a sealing nipple; Fig. 12 two sealing nipples connected to a pipe bridge and Fig. 13 an electrical machine with coolant channels of the proposed type, which is installed in a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0018] By way of introduction, it should be noted that identical parts in the different embodiments are provided with the same reference symbols or component designations, possibly with different indices. The disclosures of a component contained in the description can be transferred mutatis mutandis to another component with the same reference symbol or component designation. Furthermore, the positional information chosen in the description, such as "top," "bottom," "rear," "front," "side," and so on, refer to the directly described and illustrated figure and, in the event of a change in position, are to be transferred mutatis mutandis to the new position.

[0019] Fig. 1 shows a half-section through a schematically illustrated electrical machine 1a. The electrical machine 1a comprises a shaft 2a with a rotor 3 seated thereon, wherein the shaft 2a is rotatably mounted about a rotation axis A relative to a stator 5 by means of (rolling) bearings 4a, 4b. The rotor 3 has, in particular, rotor laminations arranged one behind the other (not shown individually), as well as rotor magnets or a rotor winding. The stator 5 has, in particular, stator laminations arranged one behind the other (not shown individually), as well as a stator winding.

[0020] In the Fig. 1 In the example shown, the first bearing 4a is located in a first housing part 6 and the second bearing 4b in a second housing part 7. The second housing part 7 is located radially inward in the area of ​​the stator 5, the first housing part 6 is located radially outward. In this example, the second housing part 7 accommodates the stator 5, which is fixedly (i.e., rotationally rigidly) connected to the second housing part 7. The two housing parts 6, 7 are enclosed by the housing 8 of the electrical machine 1 and form a first coolant channel 9 in the area of ​​the stator 5, which - as in the Fig. 1 shown example - in particular along a helical line around the stator 5. In the Fig. 1 Therefore, the only first coolant channel 9, which is cut in several places, can be seen, which is part of a first, in Fig. 1 cooling system, not shown in detail.

[0021] In the housing 8, in the area of ​​the stator 5, there is also a second coolant channel 10 of a second cooling system, which Fig. 1 is also not shown in detail. The two coolant channels 9, 10 and the housing 8 of the electric machine 1, in particular that part of the housing 8 in the region of the stator 5, thus form a heat exchanger between the first and second cooling systems.

[0022] In this example, the first coolant channel 9 is cast into the housing 8 of the electrical machine 1, and the second coolant channel 10 is formed by a tube which is arranged in the first coolant channel 9. In the example shown, the second coolant channel 10 therefore also runs along a helical line around the stator 5. Alternatively, it would be conceivable for the second coolant channel 10 to also be cast into the housing 8 of the electrical machine 1 (cf. Fig. 7 ).

[0023] Fig. 2 shows a schematic representation of how the heat exchanger formed by the two coolant channels 9, 10 can be used. A first pump 11 and an external heat exchanger 12 are connected to the first coolant channel 9. A second pump 13 and an external device 14 to be cooled are connected to the second coolant channel 10. The first coolant channel 9, the first pump 11, and the external heat exchanger 12 are part of the first cooling circuit or cooling system 15; the second coolant channel 10, the second pump 13, and the external device 14 to be cooled are part of the second cooling circuit or cooling system 16.

[0024] For example, the Fig. 2 The arrangement shown can be installed in a vehicle, wherein the electric machine 1 can in particular form a drive motor for the vehicle (see also Fig. 13 ). For example, the external heat exchanger 12 can be arranged at the front of the vehicle and cooled by the ambient air or the airstream. Of course, a blower or a fan can also be arranged in the area of ​​the external heat exchanger 12 to support the cooling effect, in particular to support the cooling effect when the vehicle is stationary. For example, water, or water mixed with antifreeze, can act as the heat transfer medium in the first cooling system 15. The electric machine 1 is cooled with the help of the cooling water that flows through the first coolant channel 9. For this purpose, heat generated in the electric machine 1 is transported by the first pump 11 via the cooling water to the external heat exchanger 12 and there released into the ambient air.

[0025] The housing 8 of the electric machine 1 simultaneously also forms a heat exchanger between the first cooling system 15 and the second cooling system 16. When the second pump 13 is in operation, heat generated in the external device 14 to be cooled is transported via the heat transfer medium in the second cooling system 16 to the electric machine 1 and transferred there to the first cooling system 15. From there, the heat is transported to the external heat exchanger 12 in the manner already described and dissipated there into the ambient air. Thus, the external device 14 to be cooled can also be cooled without the need for a separate heat exchanger.

[0026] The external device 14 to be cooled may in particular be a gearbox, and the heat transfer medium in the second cooling system 16 may in particular be gearbox oil (see also Fig. 4 ).

[0027] Of course, the basic functioning of the heat exchanger contained in the electrical machine 1 is not related to the above in connection with the Fig. 2 described embodiment, but is to be seen purely as an illustration. The arrangement shown can also be arranged at a location other than in a vehicle, and the external device 14 to be cooled does not have to be a transmission. The heat transfer media proposed for the first cooling system 15 and the second cooling system 16 are also to be seen purely as examples, and other liquid or gaseous heat transfer media can also be used. With gaseous heat transfer media, a phase change between the liquid and gaseous states can also occur. In particular, a compressor can also be provided in the cooling system in question.

[0028] It should also be noted that the coolant channels 9, 10 do not necessarily have to run along a helical line, but can also run differently. In particular, a plurality of first coolant channels 9 through which flow occurs in parallel and / or a plurality of second coolant channels 10 through which flow occurs in parallel can be provided. For example, a plurality of first coolant channels 9 can originate from a first collector and open into a second collector. In particular, the first coolant channels 9 can then run in the axial direction or along circles around the rotation axis A. The statements made regarding the first coolant channels 9 apply analogously to the second coolant channels 10.

[0029] Finally, it is also noted that the coolant channels 9, 10 - as shown in the Fig. 2 shown - advantageously flow in opposite directions and then form a countercurrent heat exchanger with the housing 8. In principle, however, the coolant channels 9, 10 can also flow in the same direction and then form a cocurrent heat exchanger with the housing 8.

[0030] Fig. 3 shows another example of an electrical machine 1b, which corresponds to the Fig. 1 It is very similar to the electrical machine 1a shown. In contrast, in the electrical machine 1b, two second coolant channels 10a, 10b are provided for each first coolant channel 9. Specifically, the second coolant channels 10a, 10b are provided as tubes in the example shown. However, it would also be conceivable for the second coolant channels 10a, 10b to be cast into the housing 8.

[0031] The second coolant channels 10a, 10b can belong to different cooling systems or form oppositely flowing sections of a single second cooling system 16. If the second coolant channels 10a, 10b belong to different cooling systems, Fig. 2 The second cooling system 16 can be doubled, allowing another device to be cooled. This is particularly advantageous when different heat transfer media are used or must be used in the two cooling systems and the additional device to be cooled cannot be integrated into the second cooling system 16.

[0032] If the second coolant channels 10a, 10b form sections of a single, second cooling system 16 through which flow occurs in opposite directions, then, for example, the heat-emitting surface in the second cooling system 16 can be doubled and the cooling capacity can therefore also be almost doubled. For example, the two second coolant channels 10a, 10b are connected at one end (see also Fig. 12 ).

[0033] Fig. 4 shows another example of an electrical machine 1c, which corresponds to the Fig. 1 which is again similar to the electrical machine 1a shown. In contrast, the rotor shaft 2b is hollow and hydraulically connected to the second coolant channel 10 of the second cooling system 16. For this purpose, the second coolant channel 10 is connected to a pipe 17, which is led into the area of ​​the rotor shaft 2b and from there through a sealing disk 18 into the interior of the rotor shaft 2b. Of course, the pipe forming the second coolant channel 10 can also be led directly into the area of ​​the rotor shaft 2b and from there through a sealing disk 18 into the interior of the rotor shaft 2b. Thus, the heat transfer medium in the second cooling system 16 also flows through the rotor shaft 2b. From there, it can also reach the interior of the electrical machine 1 via cooling / lubrication bores 19a..19c and cool the rotor 3 and the bearings 4a, 4b and - provided the second heat transfer medium is oil - also lubricate the bearings 4a, 4b.

[0034] In the Fig. 4 In the example shown, a transmission is also coupled to the electric machine 1. The Fig. 4 The arrangement shown is therefore part of a geared motor. Specifically, a pinion 20 sits directly on the rotor shaft 2b and drives another gear of the transmission (not shown). The pinion 20 runs inside a transmission housing 21, i.e., in the transmission interior B of the transmission housing 21.

[0035] In the example shown, the transmission is hydraulically connected to the second coolant channel 10 of the second cooling system 16. Specifically, this occurs via a bearing 4c arranged on the rotor shaft 2b. The flow direction F indicates the path of the heat transfer fluid through the rotor shaft 2b and through the bearing 4c into the transmission interior B. The rotor shaft 2b, the bearing 4c, and the transmission interior B are thus part of the second cooling system 16 in this example.

[0036] At this point it is noted that the Fig. 4 The function described is not tied to the exact arrangement shown there, but parts can also be designed differently. For example, the gearbox can have a separate (hollow) gear shaft connected to the rotor shaft 2b. Flow through the bearing 2c is also not mandatory; the hydraulic connection between the rotor shaft 2b and the gearbox can also be established via a separate line. Other variations are also conceivable.

[0037] Fig. 5 now shows a schematic representation of the coolant channels 9, 10 of the electrical machine 1a from Fig. 1 , wherein the (inner) second housing part 7 is shown in side view isolated from the (outer) first housing part 6. That is, the (outer) first housing part 6 is in the Fig. 5 omitted.

[0038] Fig. 6 is similar to Fig. 5 , however, shows a schematic representation of the coolant channels 9, 10 of the electrical machine 1a from Fig. 3 .

[0039] Fig. 7 is similar to Fig. 5 , however, shows a schematic representation of coolant channels 9, 10, both of which are cast into the housing 8 of the electric machine 1. In this example, the second coolant channel 10 is not arranged in, but next to the first coolant channel 9. In contrast to the representation of the Fig. 5 the (outer) first housing part 6 is shown here in section.

[0040] Fig. 8 is again similar to Fig. 7 , however, the second coolant channel 10 is formed by a separate pipe which is arranged in a groove in the second housing part 7.

[0041] Fig. 9 is again the Fig. 5 similar. In contrast, however, the coolant channels 9, 10 do not run along a helical line with a constant pitch, but rather the coolant channels 9, 10 run along circles around the rotation axis A over a wide circumferential area. Only in a narrow circumferential area does the course of the coolant channels 9, 10 have an axial component.

[0042] Fig. 10 shows a first example of a sealing nipple 22a, which is installed in a first plate 23 and which is sealed to a second plate 24 by means of a sealing ring 25. The sealing nipple 22a can, in particular, be hydraulically connected to the second coolant channel 10 and can be designed for connecting a hose or pipe, which is also part of the second cooling system 16. The first plate 23 and the second plate 24 can be part of the first housing part 6 and the second housing part 7, respectively.

[0043] Fig. 11 shows a second example of a sealing nipple 22b, which is again installed in a first plate 23 and which is sealed to a second plate 24 by means of a sealing ring 25. The sealing nipple 22b can again be hydraulically connected to the second coolant channel 10 and can be designed for connecting a hose or pipe, which is also part of the second cooling system 16.

[0044] Fig. 12 shows an example of a hose or pipe connection that is similar to Fig. 10 shown example for a hose or pipe connection. However, two sealing nipples 22a, 22a' are provided. For example, the sealing nipple 22a can be hydraulically connected to the second coolant channel 10a and the sealing nipple 22a' can be hydraulically connected to the second coolant channel 10b of the Fig. 3 The two sealing nipples 22a, 22a' can therefore be part of two different cooling systems, or - as shown in the Fig. 12 the case - belong to one and the same cooling system 16. For this purpose, the two sealing nipples 22a, 22a' are connected to a connecting pipe or a pipe bridge 26 or a hose. As a result, the coolant flows through the second coolant channels 10a, 10b in opposite directions. The proposed measures allow the electrical machine 1b to be easily adapted to different applications and can be used for different cooling systems 16 without connecting the two sealing nipples 22a, 22a' and for one and the same cooling system 16 with connecting the two sealing nipples 22a, 22a'.

[0045] The Fig. 13 Finally, the electric machine 1 installed in a vehicle 27 is shown. The vehicle 27 has at least two axles, at least one of which is driven. Specifically, the electric motor 1 is connected to an optional transmission 28 and a differential gear 29. The half-axles 30 of the rear axle are connected to the differential gear 29. Finally, the driven wheels 31 are mounted on the half-axles 30. The vehicle 27 is driven at least partially or temporarily by the electric machine 1. This means that the electric machine 1 can serve to drive the vehicle 27 alone or, for example, can be provided in conjunction with an internal combustion engine (hybrid drive).

[0046] In particular, the transmission 28 and / or the differential gear 29 can support the device 14 to be cooled in the Fig. 2and thus be part of the second cooling circuit 16. The transmission 28 can, in particular, be flanged directly to the electric machine 1, and the differential gear 29 can also be integrated into the transmission 28. In particular, the electric machine 1, the transmission 28, and the differential gear 29 can form a structural unit.

[0047] At this point, it should also be noted that the electric machine 1 or the additional external device 14 can be not only cooled but also heated using the proposed measures. For example, the electric machine 1 and the transmission 28 can be preheated at low outside temperatures. Heat transfer occurs in the opposite direction to cooling. A heater may be provided for this purpose in the first cooling circuit 15 and / or the second cooling circuit 16.

[0048] Finally, it is noted that the scope of protection is determined by the patent claims. However, the description and drawings must be used to interpret the claims. The features contained in the figures can be interchanged and combined with one another as desired. In particular, it is also noted that the devices depicted may in reality comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size.

Claims

1. Electric machine (1, 1a..1c), comprising: a housing (8), a stator (5) arranged in the housing (8) and fixedly connected to it, and a rotor (3) arranged in the housing (8), which is arranged on a rotor shaft (2a, 2b) and rotatable supported relative to the stator (5) about the axis of rotation (A) of the rotor (3) and the rotor shaft (2a, 2b), wherein the housing (8) comprises at least a first coolant channel (9) of a first cooling circuit (15) in the area of the stator (5), wherein in the housing (8) at least one second coolant channel (10, 10a, 10b) of a second cooling circuit (16) is arranged in the area of the stator (5), and the housing (8) of the electric machine (1, 1a..1c) forms a heat exchanger between the first cooling circuit (15) and the second cooling circuit (16), characterized in that the at least one first coolant channel (9) is cast into the housing (8) of the electric machine (1, 1a..1c), and the at least one second coolant channel (10, 10a, 10b) is formed by a tube, which is arranged in the at least one first coolant channel (9).

2. Electric machine (1, 1a..1c) according to claim 1, characterized in that the electric machine (1, 1a..1c) comprises a sealing nipple (22a, 22a', 22b), which is hydraulically connected to the at least one second coolant channel (10, 10a, 10b) and is designed for connecting a hose or pipe.

3. Electric machine (1, 1a..1c) according to claim 1 or 2, characterized in that the at least one first coolant channel (9) and the at least one second coolant channel (10, 10a, 10b) run helically.

4. Electric machine (1, 1a..1c) according to one of the claims 1 to 3, characterized in that two second coolant channels (10, 10a, 10b) are provided per first coolant channel (9), which belong to different cooling circuits, or form oppositely flowed-through sections of a single second cooling circuit (16).

5. Electric machine (1, 1a..1c) according to one of the claims 1 to 4, characterized in that the rotor shaft (2b) is hollow and hydraulically connected to the at least one second coolant channel (10, 10a, 10b) of the second cooling circuit (16).

6. Gear motor, comprising a gearbox and an electric machine (1, 1a..1c) coupled to the gearbox according to one of claims 1 to 5, characterized in that the gearbox is hydraulically connected to the at least one second coolant channel (10, 10a, 10b) of the second cooling circuit (16).

7. Gear motor according to claim 6, characterized in that the rotor shaft (2b) is hollow and hydraulically connected to the gearbox via a bearing (4c) arranged on the rotor shaft (2b), and the rotor shaft (2b) and the bearing (4c) form part of the second cooling circuit (16).

8. Vehicle (27) with at least one driven axle, characterized in that said drive is at least partially or temporarily provided by the electric machine (1, 1a..1c) according to one of the claims 1 to 5 or by a gear motor according to claim 6 or 7.