DE102018218811A1 - Electrical machine with a fluid cooling device - Google Patents

Abstract

An electrical machine (1) with a stator (4), a rotor (7) and with a fluid cooling device (15) is described, the rotor (10) being rotatable about an axis (A) by means of a rotor shaft (10) to the stator (4). The fluid cooling device (15) has a cooling tube (16) which is fixed by means of a first section (16a) to a fastening area (11f) of a support element (17) fixed to the stator (4) and which is connected to a fluid inlet (18 ) is connected. The cooling tube (16) extends with a second self-supporting section (16b) axially within a central recess (10a) of the rotor shaft (10) and forms an annular space (10b) with the rotor shaft (10) so that the cooling tube (16) is in fluid communication with the annular space (10b) and with a fluid outlet (19). A sealing area (20) with a sealing element (21) is provided between the rotor shaft (10) and the carrier element (17) ) lying area (22) of the electrical machine (1) at least substantially prevented. It is provided that a fluid return flow channel (11g) which is in fluid communication with the fluid outlet (19) is provided on the fastening area (11f).

Description

The invention relates to an electrical machine with a fluid cooling device according to the preamble of claim 1, as already with the WO 2016/050534 A1 has become known. To cool the rotor of the electrical machine described there, a lance-shaped cooling tube is axially introduced into a section of a rotor shaft designed as a hollow shaft, through which a cooling fluid can flow into an annular space between the latter and the rotor shaft and can absorb heat loss from the rotor. The cooling tube is fixed axially on one side with a first section to a fixed support element and projects into the rotor shaft with a second, free section. The coolant can flow in and out on the same end face of the electrical machine, as a result of which only a sealing element between the rotating rotor and the fixed elements of the machine is required.

Due to space constraints, there is a desire to make such an electrical machine more compact.

The above object is achieved by an electrical machine with the features specified in claim 1. Advantageous refinements and developments of the invention can be found in the dependent claims and the following description of the figures.

Within the scope of the present invention, an electrical machine with a fluid cooling device is proposed, which comprises a stator and a rotor and the rotor is mounted rotatably about an axis relative to the stator by means of a rotor shaft. The fluid cooling device has a cooling tube which is fixed by means of a first section to a support element fixed to the stator and which is connected to a fluid inlet. The cooling tube extends with a second self-supporting section axially within a central recess of the rotor shaft and forms an annular space with the rotor shaft, so that the cooling tube is in fluid communication with the annular space and with a fluid outlet. A sealing area with a sealing element is provided between the rotor shaft and the carrier element, which at least substantially prevents fluid from flowing into a space area of the electrical machine that is outside the sealing area when a cooling fluid flows through from the fluid inlet to the fluid outlet. The rotor shaft can be closed in a fluid-tight manner on the axial side facing away from the fluid inlet. Furthermore, the fluid inlet and the fluid outlet can be formed jointly on one and the same end face of the electrical machine and, in still further respects, in particular on a bearing plate functioning as a carrier element.

According to the invention, it is provided in the electrical machine that a fluid backflow channel which is in fluid communication with the fluid outlet is provided on the fastening region for the cooling tube which is formed on the carrier element.

The proposed design of a fluid return flow channel directly on the fastening area allows the part of the fluid cooling device provided on this end area of the electrical machine to be made more compact and space to be saved. A construction space provided for a passage for cooling fluid flowing back between the fixed section of the sealing element and the fastening area can be saved as a result of the proposal or used in some other way. The fluid return flow channel can be designed in a variety of ways, as will be explained below by way of example.

According to an advantageous embodiment, the sealing element can be formed in two parts and fixed with a first section on the fastening area and with a second section on the rotor shaft.

The fastening region can advantageously be designed as an axial extension projecting from a base body of the end shield. The cooling tube can be fixed to the fastening area in a simple manner in a fluid-tight manner by an interference fit.

An axially particularly compact arrangement can be achieved by the fastening region being designed coaxially with the axis of rotation and at least partially protruding into the rotor shaft and thereby axially overlapping with it. In a further embodiment, the sealing element can be fixed with the first section on a free end region of the axial extension and with the second section on a diameter step of the rotor shaft. The sealing element can thus be arranged entirely within the rotor shaft.

Furthermore, the space area lying outside the sealing area can comprise an annular gap formed between the sealing element and the rotor shaft, which is in fluid communication with a leakage space via a leakage channel. A portion of cooling fluid that passes through the sealing region of the sealing element can thus first be collected and collected within the rotor shaft. In this way, the mutually interacting sealing surfaces with a comparatively small diameter are formed, whereby the effectiveness of the sealing element can be improved and the proportion of a leakage fluid passing through the sealing element can be reduced.

It goes without saying that the return flow channel and the leakage channel should advantageously be fluidically separated. To separate these channels, according to a preferred embodiment, the fluid return flow channel can run between the cooling tube and the fastening area, in particular an inner peripheral area of the fastening area. According to a variant which is favorable in terms of production technology, the fluid return flow channel can comprise at least one groove formed on the fastening region on an inner circumferential region, the open side of which is delimited radially on the inside by an outer circumferential surface of the cooling tube. The fluid backflow channel can be formed completely or alternatively with its entire cross section in the material of the fastening area. In a further embodiment, the fluid return flow channel can also run between the fastening area and the fixed first section of the sealing element or a further element, in particular a cover sleeve attached to the fastening area. In this case, the fluid return flow channel can therefore be provided on an outer circumferential region of the fastening region and, in particular, comprise a groove that is open radially outwards and is closed circumferentially by the first section of the sealing element or the cover sleeve.

According to a further advantageous embodiment, the sealing element can be embodied in a particularly compact manner as an axial mechanical seal.

The invention is explained below by way of example using an embodiment shown in the figures.

• 1 eine als Fahrzeugachsantrieb ausgebildete elektrische Maschine mit einer Fluid-Kühleinrichtung mit einem Kühlrohr in einer Axialschnittdarstellung gemäß einem ersten Ausführungsbeispiel;
• 2 ein vergrößerter Ausschnitt der Fluid-Kühleinrichtung von 1 im Bereich eines Lagerschildes der elektrischen Maschine;
• 3 eine perspektivische Darstellung der elektrischen Maschine im Bereich des Lagerschilds von 3;
• 4 eine perspektivische Ansicht eines an einem Gehäuse der elektrischen Maschine ausgebildeten Kühlmittelflansches;
• 5 eine gegenüber den 1, 2 modifizierte elektrische Maschine mit einer Fluid-Kühleinrichtung mit einem Kühlrohr in einer ausschnittweisen Axialschnittdarstellung im Bereich eines Lagerschildes gemäß einem zweiten Ausführungsbeispiel;
• 6a eine innere der Fluid-Kühleinrichtung von 5 mit einem an einem Lagerschild vorgesehenen Befestigungsbereich für ein Kühlrohr;
• 6b eine ausschnittweise stirnseitige Außenansicht des Lagerschilds von 6a mit dem Befestigungsbereich.

Show it:

• 1 an electrical machine designed as a vehicle axle drive with a fluid cooling device with a cooling tube in an axial sectional view according to a first exemplary embodiment;
• 2nd an enlarged section of the fluid cooling device of 1 in the area of a bearing plate of the electrical machine;
• 3rd a perspective view of the electrical machine in the area of the bearing plate of 3rd ;
• 4th a perspective view of a coolant flange formed on a housing of the electrical machine;
• 5 one versus the 1 , 2nd modified electrical machine with a fluid cooling device with a cooling tube in a partial axial section in the area of a bearing plate according to a second embodiment;
• 6a an interior of the fluid cooler of 5 with a fastening area for a cooling pipe provided on a bearing plate;
• 6b a partial front view of the end shield of 6a with the attachment area.

The figures show an electrical machine 1 , which is provided and designed in particular for driving an electric or hybrid vehicle. In particular, the electrical machine 1 intended for installation in or on a vehicle axle and thus provides an electric axle drive in conjunction with other components 2nd The electrical machine 1 thus delivers its power to vehicle wheels for moving the vehicle. In this respect, the electrical machine explained in detail below 1 going beyond that also an electric vehicle drive and a vehicle with such an electric machine 1 described.

The electrical machine 1 includes one in a housing 3rd fixed stator 4th with a stator laminated core 5 and with a stator winding 6 and a rotor 7 with a rotor laminated core 8th and with a short-circuit cage 9 . The electric machine 1 is thus designed as an asynchronous machine. The rotor 7 is by means of a rotor shaft 10th , one on a first end shield 11 arranged first camp 13 and one on a second end shield 12th arranged second camp 14 around an axis A rotatable to the stator 4th stored. The rotor shaft 10th stands with an in 1 gearbox shown on the left 36 in operative connection, which can transmit the engine torque to vehicle wheels via further transmission elements, not shown here in the drawing.

The electrical machine 1 has a fluid cooling device through which a cooling fluid can flow 15 on, which absorbs a dissipated heat to an outside of the electrical machine 1 heat exchanger located.

The fluid cooler 15 includes a metallic cooling tube 16 which at one to the stator 4th fixed support element 17th , especially on the first end shield 11 is fixed and which one via an axial fluid inlet opening 16f with one on the end shield 11 provided fluid inlet 18th communicates. The cooling tube has one lance-shaped shape, with its axial extension L many times larger than its diameter D is. In the exemplary embodiment, this ratio is L / D> 10, in particular L / D> 15 and is approximately approximately 17th . The cooling pipe 16 is axially only on one side by means of a first section 16a through the end shield 11 stored and extends with its larger second free-standing section 16b in the axial direction within a central recess 10a the rotor shaft 10th and forms to the rotor shaft 10th an annulus 10b out. An aspect ratio of a length of the first section 16a to a length of the second section 16b , that is the ratio of the length of the fastened section 16a to the length of the unpaved, free section 16b is bigger 10th and is approximately approximately 14 .

The cooling pipe 16 is axially open on both sides and is therefore in the 1 shown installed state via an axial fluid outlet opening 16e simultaneously with the annulus 10b and also with one on the first end shield 11 provided fluid outlet 19th in fluid communication. The first end shield 11 points to the formation of the fluid inlet 18th a central first through opening 11a and to form the fluid outlet 19th a second through opening arranged radially to the first through opening 11b on. Both through openings 11a , b thus occur on the rotor 7 facing mounting surface 11c from the end shield 11 out.

Between the rotor shaft 10th and that as a carrier element 17th acting end shield 11 is a sealing area 20th with a sealing element 21 intended. The sealing element 21 has the task of flowing through the cooling fluid from the fluid inlet 18th to the fluid outlet 19th a fluid transfer into an outside of the sealing area 20th lying area 22 of the electrical machine 1 to prevent at least essentially.

The sealing element 21 is available as an axial mechanical seal 23 is trained. The mechanical seal 23 includes a first section 23a which on the support element 17th is defined and further comprises a second section 23b which on the rotor shaft 10th is fixed and which one with the first section 23a is in a sealed connection. Here is the second section 23b the mechanical seal 23 at least partially axially overlapping to the first bearing 13 arranged. That in the annulus 10b in the axial direction to the fluid outlet 19th flowing cooling fluid passes the sealing area 20th and is then replaced by a radial between an attachment area 11f of the end shield 11 or generally of the carrier element 17th and the second section 23b trained fluid passage 42 finally passed through the through opening 11b to the fluid outlet 19th to get. The cooling fluid can radially outside the mounting area 11f flow past.

Furthermore, the first camp 13 both on the mechanical seal 23 facing axial side as well as on the rotor core 8th facing axial side between a radially inner bearing ring 13a and a radially outer bearing ring 13b acting sealing arrangement 13c with two sealing washers 13d , e on. The warehouse interior 13f is further sealed against ingress of cooling fluid by means of a high speed grease. On the one hand, this makes the warehouse 13 lubricated and on the other hand, the created grease barrier prevents fluid from penetrating into the inner space 22 of the electrical machine 1 avoided.

For a noticeable increase in the fluid-cooled inner circumferential surface of the rotor shaft 10th and thus for the purpose of further improving the cooling effect, an inner diameter 10c the rotor shaft 10th or the central recess there 10a in the area of an axial extension of the rotor laminated core 8th be larger than in the area of the first bearing 13 .

As can be seen, the rotor shaft 10th formed as a hollow shaft and at the fluid inlet 18th Axial side facing away fluid-tight by a closure 24th locked. The fluid flow is experienced by the coaxial arrangement of the rotor shaft 10th and cooling pipe 16 a reversal of direction against the inflow direction and can on the axial side of the fluid inlet 18th flow out again, for which purpose only a sealing arrangement in the form of the sealing element on this side 21 is required.

From the first end shield 11 are the cooling pipe 16 , the first camp 13 and the stator-fixed section 23a of the sealing element 23 added. The first end shield 11 also takes one with the rotor shaft 10th interacting electrical equipotential bonding element 25th on. This is a potential equalization element 25th a slip ring arrangement 26 provided, which occurs as shaft voltages potential differences between the stator 4th and the rotor 7 degrades through electrical short circuit. The potential equalization element 25th is axially adjacent to the first bearing 13 arranged, in particular axially between the bearing 13 and the rotor laminated core 8th .

The cooling pipe 16 is on the one on the end shield 11 or generally on the support element 17th provided attachment area 11f fixed in a fluid-tight manner. In particular, the cooling pipe 16 by means of a press fit into one of a base body 11d of the end shield 11 protruding tubular axial extension 11e arranged which the fastening area 11f trains. The attachment area 11f and the rotor shaft 10th are coaxial with each other around the axis A educated. It can be seen in the figures that the fastening area 11f axially partially with the stator-fixed section 23a of the sealing element 21 or the mechanical seal 23 covered.

Returning to the assembly area 11c is a cover element there 27 made of a plastic with a web arrangement 27a arranged in a fluid-tight manner. Are by the web arrangement 27a between the end shield 11 and the cover element 27 a fluid feed channel 28 and a fluid drain channel 29 educated. The channels mentioned 28 , 29 can at least in sections alone from the cover element 27 be bordered. If such a cover element is dispensed with 27 can the fluid inlet channel 28 and the fluid drain channel 29 also in the first end shield 11 be trained.

The housing 3rd of the electrical machine 1 is a cast part made of a light metal material, in the present case made of an aluminum material. The housing 3rd forms a stator at the same time 4th external fluid cooling jacket 30th with a fluid channel arrangement 31 out. The housing 3rd points to the first end shield 11 facing side an integrally formed coolant flange 32 with two fluid channel sections 32a , b on which here with the fluid inlet channel 28 and the fluid drain channel 29 of the cover element 27 are in fluid communication. The fluid channel section 32a forms an external coolant connection 40 out. Another external coolant connection, not shown here in the drawing, can be located, for example, in another position of the stator cooling jacket or in power electronics for controlling the electrical machine 1 be arranged, which with their housing and with their cooling circuit with the electrical machine 1 and with the fluid cooling device formed there 15 connected is. The further fluid channel section 32b forms a connection channel to the fluid cooling jacket 30th of the stator 4th out. The fluid cooler 15 can thus have a cooling section 15a for cooling the rotor 7 and a cooling section 15b for cooling the stator 4th have, which are successively flowed through by the cooling fluid and a fluid connection provided between them as a solid, tubeless connection channel 32b is trained.

Outside the sealing element 21 , that is on the side of the mechanical seal facing away from the flowing cooling fluid 23 is a leakage room 33 with a fluid collection area 34 provided in which a through the sealing area 20th passing portion of the cooling fluid can enter and be collected. The leakage room 33 also has a gas collection area 35 on which in an operating position of the electrical machine 1 opposite the fluid collection area 34 is geodetically higher. When using a cooling fluid with at least one volatile component, this can be done via the mechanical seal 23 escape and get into the gas collection area 35 collect.

If the cooling fluid exudes a solid-shaped component when the volatile component escapes, this component is also removed from the fluid collection area 34 added. To remove the solid-form component is at the fluid collection area 34 a lockable opening 34a with a removable cover 34b intended.

To remove one in the fluid collection area 34 Existing cooling fluid is a closable fluid drain opening 34c with a drain element 34d , in particular a drain plug or a drain plug. The fluid drain opening 34c is in an operating position of the electrical machine 1 oriented essentially geodetically downwards and opposite a gas discharge opening 35a of the gas collection area 35 geodetically arranged lower. The engagement opening of the cover is for easy removal of solids-like components 34b with a larger cross section than the fluid drain opening 35a educated.

The fluid drain opening 34c is provided at least approximately at a 6 o'clock position, that is to say between a 5 o'clock and a 7 o'clock position. The gas drain opening 35a on the other hand is provided at least approximately at a 12 o'clock position, that is to say between an 11 o'clock and a 01 o'clock position. The fluid collection area 34 and the gas collection area 35 are provided at least approximately in the same axial position. The mechanical seal can also be used 23 are at this axial position or at least axially with the fluid collection area 34 and / or the gas collection area 35 overlap.

The gas drain opening 35a of the gas collection area 35 also has a pressure compensation element 41 on, causing gas to escape from the gas collection area 35 is made possible. The pressure compensation element 41 comprises a semipermeable membrane which is permeable to air to allow pressure equalization, but is not permeable to fluid.

As mentioned earlier, is for bearing the rotor 7 in addition to the first camp 13 axially spaced the second bearing 14 provided which, if necessary, can also be designed axially on one or both sides with sealing rings and with a lubricant filling. The warehouse 14 is radial between the rotor shaft 10th and the second End shield 12th provided, with the rotor core 8th in an axial space between the first and second bearings 11 , 12th extends. As can be seen, the central recess extends for the purpose of improved cooling 10a inside the rotor shaft 10th axially through the second bearing 14 through it. The cooling pipe 16 extends within the rotor shaft 10th axially also via the second bearing 12th out. As can be seen further, the inside diameter of the rotor shaft 10th in the area of the axial extension of the rotor laminated core 8th and in the area of the second warehouse 12th larger than in the area of the first warehouse 11 .

In the illustrated embodiment, the rotor shaft has 10th one axially over the second bearing 12th protruding and into the transmission 36 leading shaft section with a gear wheel 37 trained output element 38 on. The central recess 10a the rotor shaft 10th extends axially into the area of the driven element 38 and can thus also be flowed through by the cooling fluid. According to a modification of the arrangement, the cooling pipe can 16 also extend axially into the area mentioned. The output element 38 and thus further elements in heat exchange and / or one outside the rotor shaft 10th Lubricant or coolant present can thus also be in the range of action of the fluid cooling device 15 arrive and be cooled.

As can be seen further in the figures, the output element 38 on the rotor shaft 10th axially between the second bearing 14 and a third camp 39 arranged. The central recess is sufficient 10a the rotor shaft 10th axially to the area of the third bearing 39 approach and is thus flowed through by the cooling fluid up to this position. The third camp 39 is thus also in the effective range of the fluid cooling device described above 15 .

The 5 , 6a and 6b showed a detail of one versus the arrangement of 1 in the area of the first end shield 11 , the fluid outlet 19th and the mechanical seal 23 modified fluid cooling device 15 , which is described in detail below. This embodiment is based on the same, above with reference to the 1-4 explained basic structure. The features and design variants described for this purpose should also apply or be present except for the differences described below.

The cooling pipe 16 is again with the first section 16a at the attachment area 11f fixed and extending with the second cantilevered section 16b axially within the central recess 10a the rotor shaft 10th . The cooling pipe 16 forms to the rotor shaft 10th the annulus 10b out so the cooling tube 16 with the annulus 10b and with the fluid outlet 19th is in fluid communication. The rotor shaft 10th is, as previously explained, at the fluid inlet 18th facing away from the axial side fluid-tight, including the recess 10a is only axially open on one side. The fluid inlet 18th and the fluid outlet 19th are here together on one and the same end face of the electrical machine 1 and in particular on the as a carrier element 17th acting end shield 11 educated. Between the rotor shaft 10th and the carrier element 17th is also the sealing area 20th with the sealing element 21 provided which, when a cooling fluid flows through from the fluid inlet 18th to the fluid outlet 19th a fluid transfer into the outside of the sealing area 20th lying area 22 of the electrical machine 1 at least essentially prevented.

In this embodiment it is provided that on the fastening area 11f one with the fluid outlet 19th fluid backflow channel in fluid communication 11g is trained.

Another difference from the first exemplary embodiment explained above is the axial mechanical seal 23 with the first section 23a immediately at the attachment area 11f and with the second section 23b on the rotor shaft 10th fixed. The attachment area 11f is again as one of a basic body 11d of the end shield 11 protruding axial process 11e trained on the cooling tube 16 is fluid-tight by an interference fit. The attachment area 11f is coaxial to the axis A formed, at least partially protrudes into the rotor shaft 10th and axially overlaps with it. As in 5 recognizable is the sealing element 21 with the first section 23a at a free end area 11h of the axial process 11e and with the second section 23b at a diameter step 10d the rotor shaft 10th fixed.

As can be seen further, this includes outside the sealing area 20th lying area 22 one between the sealing element 21 and the rotor shaft 10th trained annular gap 22a which has a leakage channel 33a with the leakage room 33 is in fluid communication. One through the sealing area 20th of the sealing element 21 As a result, the proportion of cooling fluid that passes through can initially be inside the rotor shaft 10th to be caught and collected. The sealing element 21 is therefore completely within the rotor shaft 10th arranged.

The fluid backflow channel 11g and the leakage channel 33a are fluidically separated. The fluid backflow channel 11g in the present case comprises four on the inner circumference of the fastening area 11f trained axially extending grooves 111g , 112g , 113g , 114g which on the now open inner peripheral surface 11j through an outer peripheral surface 16c of the cooling pipe 16 are closed. Instead of the through opening 11b of the first embodiment ( 2nd ) are inclined channel sections 11k respectively. 111k , 112k , 113k , 114k provided which on the mounting surface 11c together in an arcuate recess 11l of the fluid outlet 19th flow out. The grooves 111g-114g are axially continuous for manufacturing reasons and flow into the fluid inlet 18th .

At this position, the fluid circuit is briefly closed fluidically, which creates a functionally negligible dead fluid area. The otherwise fluid-tight connection of the cooling pipe 16 to the attachment area 11f is therefore in the area of the grooves 111g , 112g , 113g , 114g canceled. Alternatively, the grooves 111g , 112g , 113g , 114g on the end shield 11 also be closed at the end, thereby the fluid inlet 18th from the fluid outlet 19th to separate in terms of flow. For example, at the axial end of the cooling tube located there 16 a collar should be provided, which the grooves 111g , 112g , 113g , 114g radially covered and thus axially closes at this position.

In the above description, designations of functional elements have been chosen in part with reference to a fixed flow direction. In the electrical machine explained, the direction of flow of the cooling fluid within the fluid cooling device is fundamentally reversible. The functional elements designated with reference to the direction of flow are given the opposite meaning when the direction of flow is reversed. This means that, for example, a section or area designated as a fluid inlet now forms the fluid outlet, etc.

Reference list

1

electrical machine

2nd

Final drive

3rd

casing

4th

stator

5

Stator laminated core

6

Stator winding

7

rotor

8th

Rotor laminated core

9

Short circuit cage

10th

Rotor shaft

10a

Recess

10b

Annulus

10c

Inside diameter

10d

Diameter step

11

End shield

11a

Through opening

11b

Through opening

11c

Mounting surface

11d

Basic body

11e

Axial process

11f

Fastening area

11 g

Fluid backflow channel

111g

Fluid backflow channel

112g

Fluid backflow channel

113g

Fluid backflow channel

114g

Fluid backflow channel

11h

End area

11j

Inner circumferential surface

11k

Canal section

111k

Canal section

112k

Canal section

113k

Canal section

114k

Canal section

111

Recess

12th

End shield

13

warehouse

13a

inner bearing ring

13b

outer bearing ring

13c

Sealing arrangement

13d, e

Sealing washer

13f

Warehouse interior

14

warehouse

15

Fluid cooling device

15a

Rotor cooling section

15b

Stator cooling section

16

Cooling pipe

16a

first section

16b

second part

16c

Outer peripheral surface

16f

axial fluid inlet opening

17th

Carrier element

18th

Fluid inlet

19th

Fluid outlet

20th

Sealing area

21

Sealing element

22

Room area

22a

Annular gap

23

Mechanical seal

23a

first section

23b

second part

24th

Clasp

25th

Equipotential bonding element

26

Slip ring arrangement

27

Cover element

27a

Bridge arrangement

28

Fluid inlet channel

29

Fluid drain channel

30th

Fluid cooling jacket

31

Fluid channel arrangement

32

Coolant flange

32a, b

Fluid channel section

33

Leakage room

33a

Leakage channel

34

Fluid collection area

34a

lockable opening

34b

Sealing cover

34c

Fluid drain opening

34d

Drain element

35

Gas collection area

35a

Gas drain opening

36

transmission

37

gear

38

Output element

39

warehouse

40

external coolant connection

41

Pressure compensation element

42

Fluid passage

A

Axis of rotation

D

diameter

L

axial extension

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for better information for the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2016/050534 A1 [0001]

Claims (9)

Electrical machine (1) with a fluid cooling device (15), comprising - a stator (4), - a rotor (7) which is rotatably mounted about an axis (A) to the stator (4) by means of a rotor shaft (10) the fluid cooling device (15) has a cooling tube (16) which is fixed by means of a first section (16a) to a fastening area (11f) of a support element (17) fixed to the stator (4) and with a fluid inlet (18) is connected and which extends with a second self-supporting section (16b) axially within a central recess (10a) of the rotor shaft (10) and with the formation of an annular space (10b) to the rotor shaft (10), wherein - the cooling tube (16) is in fluid connection with the annular space (10b) and with a fluid outlet (19) and wherein - between the rotor shaft (10) and the carrier element (17) a sealing area (20) with a sealing element (21) is provided, which at Flow of a cooling fluid from the fluid inlet (18) to the fluid outlet (19) at least substantially prevents a fluid transfer into a space (22) of the electrical machine (1) lying outside the sealing area (20), characterized in that on the fastening area (11f) a fluid connection is made with the fluid outlet (19) standing fluid backflow channel (11g) is provided. Electrical machine after Claim 1 , characterized in that the sealing element (21; 23) is fixed with a first section (23a) on the fastening area (11f) and with a second section (23b) on the rotor shaft (10). Electrical machine after Claim 1 or 2nd , characterized in that the fastening area (11f) is designed as an axial extension (11e) projecting from a base body (11d) of the bearing plate (11). Electrical machine according to one of the Claims 1 to 3rd , characterized in that the fastening area (11f) is coaxial with the axis A and at least partially protrudes into the rotor shaft (10) and overlaps axially with the latter. Electrical machine after Claim 3 or 4th characterized in that the first section (23a) is fixed to a free end region (11h) of the axial extension (11e) and the second section (23b) is fixed to a diameter step (10d) of the rotor shaft (10). Electrical machine according to one of the Claims 1 to 5 , characterized in that the space area (22) lying outside the sealing area (20) comprises an annular gap (22a) formed between the sealing element (21) and the rotor shaft (10), which has a leakage channel (33a) via a leakage channel (33a) is in fluid communication. Electrical machine after Claim 6 , characterized in that the return flow channel (11g) and the leakage channel (33a) are fluidically separate. Electrical machine according to one of the Claims 1 to 7 , characterized in that the fluid return flow channel (11g) comprises a groove (111g; 112g; 113g; 114g) formed between the cooling tube (16) and the fastening area (11f). Electrical machine according to one of the Claims 1 to 8th , characterized in that the sealing element (21) is designed as an axial mechanical seal (23).

Images