DE102014117962A1 - Electric drive system with improved cooling - Google Patents

Abstract

The invention relates to an electric drive system (1) having an electric machine (10), the electric machine (10) having a rotor (11) and a stator (12), the rotor (11) being rotatably received in the stator (12) and wherein the rotor (11) is formed with a cavity (13) for passing a cooling medium (14), and wherein the electric machine (10) has a side flange (16) in which at least one opening (17) for passing the cooling medium (14) is formed. According to the invention, an electrical control module (18) for controlling the electrical machine (10) is provided, wherein the electrical control module (18) on the side flange (16) is arranged, and wherein the electrical control module (18) has a passage (19) for passing the cooling medium (14), which merges into the opening (17) in the side flange (16).

Description

The present invention relates to an electric drive system with an electric machine, wherein the electric machine comprises a rotor and a stator, wherein the rotor is rotatably received in the stator, wherein the rotor is formed with a cavity for passage of a cooling medium, and wherein the electric machine a side flange, in which at least one opening for passing the cooling medium is formed.

STATE OF THE ART

The DE 10 2012 203 697 A1 describes an electric machine, and the rotor of the electric machine is designed with a cavity through which a cooling medium can be passed. For introducing and removing the cooling medium, the electric machine has an opening in a side flange, via which the cooling medium can be supplied and removed. To flow through the rotor, this has a shaft in which the cavity is formed, and a laminated plate package is received on the outside of the shaft. During operation of the electric machine, the heat generated in the lamination stack can be discharged through the wall of the shaft to the cooling medium, and via the cooling medium, the heat can be dissipated from the rotor of the electric machine.

The DE 10 2009 001 458 A1 describes a rotor of an electric machine with laterally mounted wheels on which blades are formed. When the rotor rotates during operation of the electric machine, the impellers convey air through the rotor in order to dissipate heat arising in the rotor.

From the DE 196 18 996 A1 For example, an electric drive system with an electric machine and with an electric control module is shown, and on the rotor of the electric machine, a machine fan is received, which generates an air flow to cool the electric machine. In this case, a part of the air flow is redirected so that the electric control module can be cooled by the air flow.

Starting from a design of an electrical machine with an enveloping body, which essentially has a cylindrical shape, cooling of the electrical machine and of the electrical control module is only possible to a limited extent effectively via the outer circumferential surface. In this case, it is desirable to internally cool a rotor, wherein an electric control module should also be cooled in a simple manner. Depending on the type of electrical machine and depending on the intended use, the electrical control module can be designed as a converter, which is also referred to as a DC / AC converter. Such converters are particularly important for drive systems that are used in electrically powered vehicles.

DISCLOSURE OF THE INVENTION

The object of the invention is the development of an electric drive system with an electric machine having an improved overall cooling. In this case, the electric drive system should be extendable starting from an electric machine with an electric control module, with an effective cooling of the electric machine and the electric control module to be achieved in a simple manner.

This object is achieved on the basis of an electric drive system according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims.

The invention includes the technical teaching that an electric control module for controlling the electric machine is provided as part of the electric drive system, wherein the electric control module is arranged on the side flange, and wherein the electrical control module has a passage for passing the cooling medium, which in the Passing opening in the side flange and has a fluidic connection with the cavity in the rotor.

Due to the direct arrangement of the electrical control module to the side flange of the electric machine, a common flow path of the cooling medium can be created both through the passage of the electrical control module as well as through the adjoining the passage cavity in the rotor of the electric machine, so that through the fluidic connection a simple and advantageous passage of the cooling medium is made possible both by the stationary electric control module and by the rotating electrical machine. Core of the invention is the passage in the electric control module, can be discharged via the heat from the electric control module to the same cooling medium, which also flows through the cavity of the rotor. Thus, a first heat transfer region can be created on a flow path, in which heat is transferred from the electric machine to the cooling medium, and a second heat transfer region can be created, in which heat passes from the electrical control module to the cooling medium.

Advantageously, in the cavity of the rotor, a guide tube for guiding the cooling medium is introduced, wherein the guide tube is adapted to the cooling medium into the cavity and / or divert. Furthermore, in the passage of the electric control module, a second guide tube for guiding the cooling medium can be introduced, wherein the guide tube can connect in the passage of the control module end to the guide tube in the cavity of the rotor or can be integrally formed therewith. Consequently, the guide tube can also be formed and arranged standing, rotating or partially standing and partially rotating, wherein a partially stationary and partially rotating guide tube may have a separation point with a standing-rotating transition. The guide tube may have a round, rectangular or other cross-section, and the guide tube does not necessarily have to have a constant cross-section in the longitudinal direction, that is to say in the direction of the shaft axis. For example, the guide tube in the rotor and / or in the control module can also taper or widen.

By arranging guide tubes in the electrical control module and in the rotor of the electric machine, the cooling medium can be introduced, for example, inside through the guide tube through the passage and into the cavity, wherein the guide tube in the cavity of the rotor is open at the end, and from the opening, the cooling medium emerge from the guide tube and enter the cavity of the rotor. By a pressure difference generated in the guide tube while the cooling medium flows outside the guide tubes back and can emerge through a ring cross-section between the passage in the electrical control module and the guide tube again. The inside wall of the passage forms the second heat transfer region, and an effective flow through the passage in the electrical control module and the cavity in the rotor is provided with the cooling medium, and this can be guided past the two heat transfer areas. According to a modified variant, the cooling medium can also be introduced into the annular gap between the guide tube and the passage, and the cooling medium can flow through the passage on the outside of the guide tubes into the cavity in the rotor. Finally, the cooling medium is forced back into the cavity via the open end of the guide tube and can emerge from the electrical drive system on the inside through the guide tubes. In this reverse flow direction, the control module is cooled more due to the temperature difference to the medium.

The rotor may have a construction with a carrier tube and flanges adjoining the carrier tube laterally, so that the cavity in the rotor is enclosed by the carrier tube and by the flanges laterally adjoining the carrier tube, and wherein the cooling medium flows through one of the two flanges in FIG the cavity can be introduced and / or redirected, and wherein the cavity expands in diameter starting from the lateral flanges in the area of the carrier tube. On the outside of the support tube, a laminated plate set of the rotor can be accommodated so that the carrier tube can advantageously have a heat transfer structure on the inside. If the cooling medium flows around or overflows the heat transfer structure on the inside in the carrier tube, then heat which is generated in the rotor and in particular in the lamination stack with further electromagnetic active parts can be transferred via the carrier tube to the cooling medium. The guide tube in the rotor of the electric machine can thereby extend through the flange, through which the cooling medium can be introduced and diverted, in particular the flange of the rotor can be formed with a flow guide extension which is designed to introduce the cooling medium into the cavity of the rotor to lead in or out. The diameter of the guide tube is smaller than the inner diameter of the Strömungsleitfortsatzes in the flange of the rotor, so that between the guide tube and the Strömungsleitfortsatz an annular gap is formed, which merges into the annular gap between the passage in the electric control module and the guide tube in the electric control module.

The passage in the electrical control module may be formed by a hollow body, wherein the non-co-rotating hollow body is introduced in the electric control module and has an axis of symmetry which coincides with the shaft axis. Advantageously, the hollow body may be formed by a heat sink with an inside and / or outside cooling fin structure. Due to the design of the hollow body in the electric control module as a heat sink with a cooling fin structure, a particularly advantageous heat transfer to the cooling medium is provided to heat electrical circuit boards and the like, which are arranged in the electric control module, via the cooling fin structure of the heat sink.

The electrical machine and in particular the electrical control module can form an annular base body, wherein the passage for passing the cooling medium coincides with a rotational axis of the annular base body, which lies in particular in the shaft axis of the rotor of the electric machine. The boards may preferably be arranged radially inside and thus close to the cooling fin structure of the heat sink in the annular base body, so that a Heat dissipation through the passage in the control module, and in particular on the designed as a heat sink hollow body can be effectively achieved. In particular, electrical components which strongly heat up during operation can be attached particularly close to the cooling rib structure of the hollow body or they can be cast with the outside cooling rib structure. The inside cooling rib structure is thereby flowed around with the cooling medium, so that a convective heat dissipation from the hollow body is achieved.

Finally, a filter element can be provided, and the filter element can be arranged so that it can be flowed through by the cooling medium. For example, the filter element can be introduced as a filter insert in the guide tube, which is arranged in the passage of the control module and via which the cooling medium, which is preferably formed by air, enters the passage and finally into the rotor. This prevents contaminants from penetrating into the passage and also into the cavity of the rotor of the electric machine, which is an important protective function, in particular for electromobile applications on partially contaminated paths.

In order to achieve a flow of the cooling medium through the guide tubes, through the cavity and through the passage, a pressure difference must be generated between the inflowing and the outflowing cooling medium in order to generate a movement in the cooling medium. In particular, a flow in the cooling medium can be caused by a blade element, through which the cooling medium can be passed through the cavity and through the passage during rotation of the rotor. For example, the blade element can be arranged on the rotor such that it also rotates during rotation of the rotor. With particular advantage, the blade element may be attached to the flow guide extension of the flange, which is part of the rotor. The vane element may have a passage through which one of the guide tubes may extend, such that the vane element causes rotation of the cooling medium into the annular gap between the guide tube and the passage in the electric machine. The cooling medium, preferably air, is thus blown out of the annular gap between the guide tube and the passage, so that the cooling medium is simultaneously sucked into the first guide tube in the passage of the control module by the negative pressure or by the resulting pressure difference.

PREFERRED EMBODIMENT OF THE INVENTION

Further, measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to FIGS. It shows:

1 An embodiment of an electric drive system with an electric machine and with an electric control module in a cross-sectional view,

2 a variant of the embodiment according to 1 with the arrangement of a blade element in the passage of the electrical control module and

3 a side view of the hollow body, through which the passage is formed in the electric control module and having a cooling fin structure.

1 shows an embodiment of an electric drive system 1 with an electric machine 10 and with an electrical control module 18 , The electric machine 10 has a machine housing 34 on and the electric control module 18 has a ring housing 35 on and both housings 34 and 35 have a cylindrical basic structure, which together form a cylinder. The essentially rotationally symmetrical machine housing 34 extends around a shaft axis 15 and is bounded laterally by a side flange 16 , On the side flange 16 is the electrical control module 18 Flanged so that the machine housing 34 with the flanged electrical control module 18 also forms a cylindrical body.

Center in the side flange 16 is the electric machine 10 with an opening 17 executed, which is formed with a circular cross section, which extends around the shaft axis 15 extends around. The electrical control module 18 is with a passage 19 executed, which also has a circular cross section and which is also around the shaft axis 15 extends around. By means of the passage 19 and the opening 17 creates a common flow path for a cooling medium 14 That is via the free opening side of the passage 19 can be introduced and discharged, so that the cooling medium 14 the passage 19 can flow through to the opening 17 the electric machine 10 to get.

To the opening 17 closes inside a cavity 13 on that in the rotor 11 the electric machine 10 is trained. The rotor 11 is shown essentially simplified and constructed has a support tube 22 on, on the side flanges 23 and 24 connect. On the outside of the carrier tube 22 is a sheet metal plate package 25 recorded, and the rotor 11 is in a manner not shown on the flanges 23 and 24 with storage 38 rotatable in the stator 12 added. In the flange shown on the right 24 is a closure element 37 inserted, through which the flange 24 is closed, and on a pin of the flange 24 closes an output element 36 on, about the rotational movement of the rotor 11 during operation of the electric machine 10 can be tapped.

The flange shown on the left 23 has a flow guide extension 28 on, attached to a hollow body 27 in the electrical control module 18 adjacent to the front. The hollow body 27 makes the passage 19 in the electrical control module 18 , and the transition between the hollow body 27 and the flow guide extension 28 is shown in simplified form, and may include, for example, a labyrinth seal or the like. For example, the two tubular bodies can also be joined together, depending on the direction in which the hollow body 27 and the flow guide extension 28 with the cooling medium 14 be flowed through.

In the cavity 13 is a guide tube 20 introduced, to which a guide tube 21 connects that in the passage 19 is introduced. The guide tube 21 is the outwardly widening contour of the hollow body 27 adapted so that a circumferential annular gap 32 between the guide tube 21 and the hollow body 27 is formed. Inside the guide tube 21 is a filter element 30 introduced, and is cooling medium 14 , For example, formed by ambient air, in the guide tube 21 initiated, this may first the filter element 30 flow through, so that the incoming cooling medium 14a is filtered. This wanders through the guide tube 21 and the subsequent guide tube 20 in the rotor 11 and exits the guide tube at the end 20 and thus enters the cavity 13 , Finally, the cooling medium can 14 at the heat transfer structure 26 inside in the carrier tube 22 heat up, then through the Strömungsleitfortsatz 28 and through the annular gap 32 to flow out again, wherein the outflowing cooling medium with 14b is designated.

Through the heat transfer structure 26 on the inside of the carrier tube 22 can heat in a particularly effective way from the lamination stack 25 to the cooling medium 14 be passed, so that inside the rotor 11 a first heat transfer area I is formed. Flows the cooling medium 14 through the flange 23 with the flow guide extension 28 back again and gets into the annular gap 32 between the guide tube 21 and the hollow body 27 , so can in the hollow body 27 a second heat transfer area II be formed. The cooling medium 14 heats up further by the heat generated in the boards shown by way of example 33 in the electrical control module 18 are present, and by the cooling medium 14 to be cooled.

2 shows a modified embodiment of the electric drive system 1 with the electric machine 10 and with the electrical control module 18 , End on the flow guide extension 28 of the flange 23 of the rotor 11 there is a blade element 31 , The rotor rotates 11 through storage 38 in the stator 12 , so promotes the blade element 31 the cooling medium 14 from the cavity 13 in the annular gap 32 between the hollow body 27 and the guide tube 21 , By the arrangement of the blade element 31 at the flow guide extension 28 with the rotor 11 mitrotierenden flange 23 becomes the blade element 31 during operation of the electric machine 10 with the speed of the rotor 11 in rotation about the shaft axis 15 offset, so that a conveying effect on the cooling medium 14 is achieved. This is done by the rotating blade element 31 , shown by way of example with individual blades, into the annular gap 32 pressed, at the same time created by the suction effect a promotion of the incoming cooling medium 14a in the guide tubes 21 and 20 , furthermore passes through the conveying action of the rotating blade element 31 the cooling medium 14 in the cavity 13 , Depending on the blade pitch and the arrangement of the blades of the blade element 31 can the passage 19 and the cavity 13 be traversed in an opposite direction.

The hollow body 27 to form the passage 19 in the electrical control module 18 is in the 1 and 2 only simplified, and for an effective cooling of the boards 33 can the hollow body 27 be designed as a heat sink, as this in 3 is shown.

3 shows a view of the hollow body 27 in arrangement in the electric control module 18 from the direction of the shaft axis 15 , Inside in the electrical control module 18 , simplified by the ring housing 35 is the passage 19 formed in which the guide tube 21 is used. Inside in the guide tube 21 is incoming cooling medium 14a shown, and in the annular gap 32 between the guide tube 21 and the hollow body 27 is effluent cooling medium 14b shown. The effluent cooling medium 14b convected at the inside cooling rib structure 29 of the hollow body designed as a heat sink 27 , The outside cooling rib structure 29 gut the boards 33 , so that by the hollow body designed as a heat sink 27 with the inside and outside cooling fin structure 29 a very good heat transfer from the boards 33 to the convective cooling medium 14b can be created. In a manner not shown in detail, the boards 33 also with the outside cooling rib structure 29 of the hollow body 27 be potted or these are at the cooling fin structure 29 attached to an improved heat transfer to the hollow body 27 to accomplish.

The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All of the claims, the description or the drawings resulting features and / or advantages, including structural details or spatial arrangements may be essential to the invention both in itself and in various combinations. In particular, the hollow body 27 in the in 3 shown embodiment both in 1 as well as in 2 Find use. Advantageously, the arrangement of the blade element 31 also in connection with an embodiment of the hollow body 27 as a heat sink with a cooling fin structure 29 according to 3 be provided.

LIST OF REFERENCE NUMBERS

1

 electric drive system

10

 electric machine

11

 rotor

12

 stator

13

 cavity

14

 cooling medium

14a

 inflowing cooling medium

14b

 outflowing cooling medium

15

 shaft axis

16

 side flange

17

 opening

18

 electrical control module

19

 passage

20

 guide tube

21

 guide tube

22

 support tube

23

 flange

24

 flange

25

 Laminations package

26

 Heat transfer structure

27

 hollow body

28

 Strömungsleitfortsatz

29

 Fin structure

30

 filter element

31

 vane element

32

 annular gap

33

 circuit board

34

 machine housing

35

 ring case

36

 output element

37

 closure element

38

 storage

I

 first heat transfer area

II

 first heat transfer area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of 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.

Cited patent literature

• DE 102012203697 A1 [0002]
• DE 102009001458 A1 [0003]
• DE 19618996 A1 [0004]

Claims (5)

Electric drive system ( 1 ) with an electric machine ( 10 ), wherein the electric machine ( 10 ) a rotor ( 11 ) and a stator ( 12 ), wherein the rotor ( 11 ) in the stator ( 12 ) is rotatably received, and wherein the rotor ( 11 ) with a cavity ( 13 ) for the passage of a cooling medium ( 14 ), and wherein the electric machine ( 10 ) a side flange ( 16 ), in which at least one opening ( 17 ) for passing the cooling medium ( 14 ), characterized in that an electrical control module ( 18 ) for controlling the electrical machine ( 10 ) is provided, wherein the electrical control module ( 18 ) on the side flange ( 16 ), and wherein the electrical control module ( 18 ) a passage ( 19 ) for passing the cooling medium ( 14 ), which in the opening ( 17 ) in the side flange ( 16 ) passes over. Electric drive system ( 1 ) according to claim 1, characterized in that in the cavity ( 13 ) of the rotor ( 11 ) a guide tube ( 20 ) for guiding the cooling medium ( 14 ), wherein the guide tube ( 20 ) is adapted to the cooling medium ( 14 ) in the cavity ( 13 ) - and / or divert. Electric drive system ( 1 ) according to claim 1 or 2, characterized in that in the passage ( 19 ) of the electrical control module ( 18 ) a guide tube ( 21 ) for guiding the cooling medium ( 14 ), wherein the guide tube ( 21 ) at the end of the guide tube ( 20 ) in the cavity ( 13 ) or formed integrally with this. Electric drive system ( 1 ) according to one of claims 1 to 3, characterized in that the guide tubes ( 20 . 21 ) are designed so that the cooling medium ( 14 ) the guide tubes ( 20 . 21 ) flows through the inside in a first flow direction and flows around the outside in an opposite second flow direction. Electric drive system ( 1 ) according to one of the preceding claims, characterized in that the cavity ( 13 ) in the rotor ( 11 ) through a carrier tube ( 22 ) and laterally to the support tube ( 22 ) subsequent flanges ( 23 . 24 ), wherein the cooling medium ( 14 ) by a flange ( 23 ) in the cavity ( 13 ) and wherein the cavity ( 13 ) in the region of the carrier tube ( 22 ) is widened in diameter. Electric drive system ( 1 ) according to claim 5, characterized in that on the outside of the support tube ( 22 ) a lamination stack ( 25 ) of the rotor ( 11 ) and wherein the support tube ( 22 ) inside a heat transfer structure ( 26 ) having. Electric drive system ( 1 ) according to one of the preceding claims, characterized in that the passage ( 19 ) through a hollow body ( 27 ) is formed, wherein the hollow body ( 27 ) in the electrical control module ( 18 ) is introduced and has an axis of rotation with the shaft axis ( 15 ) coincides. Electric drive system ( 1 ) according to claim 7, characterized in that the hollow body ( 27 ) by a heat sink with an inside and / or outside cooling fin structure ( 29 ) is formed. Electric drive system ( 1 ) according to one of claims 7 or 8, characterized in that the flange ( 23 ) of the rotor ( 11 ) with a flow guide extension ( 28 ) is formed, the front side of the hollow body ( 27 ) adjoins, projects in sections or encloses them in sections. Electric drive system ( 1 ) according to one of the preceding claims, characterized in that a filter element ( 30 ) provided with the cooling medium ( 14 ) is arranged throughflow. Electric drive system ( 1 ) according to one of the preceding claims, characterized in that the electrical control module ( 18 ) forms an annular base body, wherein the passage ( 19 ) for passing the cooling medium ( 14 ) coincides with a rotational axis of the annular body. Electric drive system ( 1 ) according to one of the preceding claims, characterized in that a blade element ( 31 ) is provided, through which the cooling medium ( 14 ) during rotation of the rotor ( 11 ) through the cavity ( 13 ) and through the passage ( 19 ) can be passed.

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