DE102023125370A1 - Electric machine with stator having direct meander cooling and an integrated nozzle opening - Google Patents

Abstract

The invention relates to an electrical machine (1) for driving a motor vehicle, comprising a stator (2) which runs in an overall annular shape and a cooling channel structure (4) which is introduced into an annular base body (3) of the stator (2) and which runs meanderingly along the circumference at least in sections, wherein the base body (3) is formed from a laminated core (5) and both the cooling channel structure (4) and a plurality of nozzle openings (8) which open towards an end face (7a, 7b) of the stator (2) are formed by different, hydraulically interconnected recesses (9) in individual sheets (10) of the laminated core (5).

Description

The invention relates to an electric machine for driving a motor vehicle, preferably a car, truck, bus or other commercial vehicle, particularly preferably an agricultural commercial vehicle, with a stator which runs in an annular shape as a whole and a cooling channel structure which is introduced into an annular base body of the stator and runs meanderingly along the circumference at least in sections.

Stators of this type with integrated cooling channel structures are already well known from the prior art. For example, CN 115021439 A differently shaped channels.

A further increase in the performance of modern electric drive motors can usually only be achieved by enlarging their components. However, this makes it increasingly difficult to dissipate the heat generated in and on the stator. It is therefore already known to cool stator components, such as the coils, from the outside in addition to the cooling channel structures inside the stator. However, additional components are required at the ends of the stator to generate and redirect these hydraulic fluid flows from the outside. Separate nozzle shields must usually be installed to direct the hydraulic fluid to the winding head, for example.

It is therefore an object of the present invention to provide an electrical machine with the highest possible rated power, which has efficient cooling, but at the same time reduces the number of components.

This is achieved according to the invention in that the base body is formed from a laminated core and both the cooling channel structure and several nozzle openings open to one end face of the stator are formed by different, hydraulically interconnected recesses/through holes in individual sheets of the laminated core.

This results in the most compact stator design possible, with jet cooling integrated directly into the meandering cooling channel structure. The result is efficient cooling of the electric motor during operation.

Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

Accordingly, it is advantageous for the most direct cooling possible of a winding head of the stator if a first lamination of the laminated core arranged at the front/axial end has the nozzle openings which are introduced into webs of this first lamination which serve to form stator teeth.

Furthermore, it is advantageous to have several radially spaced nozzle openings in the first sheet for each web. This further improves the cooling performance.

It is also advantageous if several first recesses in the first sheet forming the nozzle openings are connected to radially elongated second recesses in a second sheet arranged directly adjacent to the first sheet, with the second recesses further connected to the cooling channel structure. This allows a hydraulic fluid flow that has previously passed through the cooling channel structure and has already cooled a large portion of the stator to be used to further cool the winding head. This ensures that the available hydraulic fluid is used as efficiently as possible for cooling.

It is also advantageous if a meandering wave section of the cooling channel structure is formed by additional recesses radially outside the stator teeth. This ensures that the solid part of the stator is cooled first before the winding head is sprayed with the fluid.

Furthermore, it is advantageous if the base body has an annular, radially outwardly opening feed channel that is connected to at least one recess in a sheet metal plate serving as an inlet. This allows the hydraulic fluid to be fed to the stator as axially as possible, centrally. The stator is thus cooled as efficiently as possible.

If the stator has several base bodies arranged axially next to each other, preferably two base bodies, the stator and the electrical machine are as powerful as possible.

In this regard, it is again advantageous if at least two base bodies arranged at their ends are provided with nozzle openings, wherein the nozzle openings of a first base body are axially opposite to the nozzle openings of a second base body. This allows various components located axially adjacent to the base body, in particular the winding heads of the electrical machine, to be directly cooled.

For easier manufacturing of the laminated core/stator, it is also advantageous if the recesses are produced by stamping. It is best to form the recesses of the different laminations using different stamping tools.

The invention will now be explained in more detail below with reference to figures.

• 1 eine schematische Explosionsdarstellung eines Teils eines erfindungsgemäßen Stators einer elektrischen Maschine nach einem bevorzugten Ausführungsbeispiel, wobei verschiedene, einen Grundkörper des Stators bildende Bleche jeweils mit verschiedenen Ausnehmungen zur Ausbildung einer Kühlkanalstruktur sowie mehrerer Düsenöffnungen versehen sind,
• 2 eine perspektivische Außenansicht des Stators einer erfindungsgemäßen elektrischen Maschine, zur Veranschaulichung der prinzipiellen Position der Kühlkanalstruktur,
• 3 eine Vorderansicht eines einen Einlass aufweisenden Bleches des Blechpaketes des Grundkörpers nach 1,
• 4 bis 6 Vorderansichten weiterer Bleche, die zur Bildung der mäanderförmigen Kühlkanalstruktur eingesetzt sind,
• 7 eine Vorderansicht eines Bleches aufweisend eine radiale Verbindungsstruktur zwischen mäanderförmigen Kühlkanalstruktur und den Düsenöffnungen,
• 8 eine Vorderansicht eines Bleches aufweisend die Düsenöffnungen,
• 9 und 10 Vorderansicht weiterer Bleche mit alternativ ausgeformten Ausnehmungen zur Ausbildung der mäanderförmigen Kühlkanalstruktur,
• 11 eine Vorderansicht eines stanztechnisch bearbeiteten Bleches unter Veranschaulichung verschiedener, zur Ausbildung der verschiedenen Ausnehmungen dienenden Stanzwerkzeuge,
• 12 und 13 perspektivische Außenansichten zweier Statoren alternativer Ausführungsformen, wobei in 12 kein Mäandergang und in 13 mehr Mäandergänge als in 2 umgesetzt sind,
• 14a bis 14c Vorderansichten eines Blechzusammenbaus (14a) bestehend aus zwei Blechen (14b und 14c) zur Bildung der Düsenöffnungen gemäß einer alternativen Ausführungsform, sowie
• 15a uns 15b Vorderansichten eines Blechzusammenbaus bestehend aus zwei Blechen (15a und 15b) zur Bildung der Düsenöffnungen, jedoch ohne Mäandergang, gemäß einer alternativen Ausführungsform.

They show:

• 1 a schematic exploded view of a part of a stator according to the invention of an electrical machine according to a preferred embodiment, wherein various sheets forming a base body of the stator are each provided with different recesses for forming a cooling channel structure and several nozzle openings,
• 2 a perspective external view of the stator of an electrical machine according to the invention, to illustrate the basic position of the cooling channel structure,
• 3 a front view of a sheet having an inlet of the laminated core of the base body according to 1 ,
• 4 to 6 Front views of additional sheets used to form the meandering cooling channel structure,
• 7 a front view of a sheet having a radial connecting structure between the meandering cooling channel structure and the nozzle openings,
• 8 a front view of a sheet metal showing the nozzle openings,
• 9 and 10 Front view of further sheets with alternatively shaped recesses for the formation of the meandering cooling channel structure,
• 11 a front view of a punched sheet metal showing various punching tools used to form the various recesses,
• 12 and 13 perspective external views of two stators of alternative embodiments, in which 12 no meandering and in 13 more meanders than in 2 are implemented,
• 14a to 14c Front views of a sheet metal assembly ( 14a) consisting of two sheets ( 14b and 14c ) for forming the nozzle openings according to an alternative embodiment, and
• 15a us 15b Front views of a sheet metal assembly consisting of two sheets ( 15a and 15b) for forming the nozzle openings, but without meandering, according to an alternative embodiment.

The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals.

In connection with the 1 and 2 First, a stator 2 of an electrical machine 1 according to the invention can be seen. The electrical machine 1 is dimensioned such that it is preferably used as a drive motor of a motor vehicle, namely in particular an agricultural utility vehicle.

It is in 2 It can be seen particularly well that the stator 2 has at least one base body 3, here even two base bodies 3a and 3b. The base bodies 3; 3a, 3b are each composed of laminated cores 5, here even completely formed by the laminated core 5. A laminated core 5 has, in the usual way, largely similarly designed individual sheets 10, which are stacked in the axial direction and ultimately form several axially aligned, radially inwardly opening slots 15 / recesses in which the windings 16 of a coil of the stator 2 are positioned. Towards the axial end sides of the stator 2, the windings 16 are redirected / bent in the usual way and thereby form winding heads 17. As in 2 As can be seen, a first base body 3a is surrounded by the winding head 17 towards its first end face 7a, and a second base body 3b is surrounded by a winding head 17 towards a second end face 7b (facing away from/opposite the first end face 7a). The two base bodies 3a, 3b are of identical design, but are positioned axially mirror-symmetrically/mirror-inverted.

In addition to the annular stator 2, the electric machine 1 has, in the usual way, a rotor (not shown here for the sake of clarity), which is rotatably driven by the stator 2 and is arranged (radially) within the stator 2. The directions used in the present case, axial, radial and circumferential, are to be understood in relation to a rotational axis of the rotor, which is congruent with a central axis/longitudinal axis of the stator and in 2 is indicated by the reference symbol 6. The term axial/axial direction is therefore understood to mean a direction along/parallel to the longitudinal axis 6, the term radial/radial direction is understood to mean a direction perpendicular to the longitudinal axis 6, and the term circumferential direction is understood to mean a direction along a circular line concentrically encircling the longitudinal axis 6.

In 2 It can also be seen that a radially outwardly open, annularly circumferential feed channel 14 in the form of a groove is provided for supplying a hydraulic fluid into a cooling channel structure 4 of the stator 2. During operation, hydraulic fluid is supplied to the cooling channel structure 4 via this feed channel 14.

In 1 The detailed design of the cooling channel structure 4 can be seen. The cooling channel structure 4 is formed by several recesses 9a, 9b, 9c in various sheets 10; 10a, 10b, 10c of the laminated core 5. Axially overlapping/connected recesses 9a, 9b, 9c form the channel structure 4. This ultimately results in a meandering wave region 13 of the cooling channel structure 4, which guides the hydraulic fluid along the circumference of the stator 2 through the base body 3 during operation.

According to the invention, a nozzle device is provided at one axial end of the cooling channel structure 4, which nozzle device has a plurality of nozzle openings 8 formed as first recesses 9a in a further (first) sheet 10a. The nozzle openings 8 are also formed as through holes and positioned such that a hydraulic fluid emerging from them during operation towards the surroundings of the base body 3 directly sprays/rinses the winding head 17 of the stator 2. The nozzle openings 8 are positioned radially within the cooling channel structure 4. The nozzle openings 8 are introduced into radially inwardly projecting webs 12 of the first sheet 10a. The nozzle openings 8 for each web 12 are spaced apart from one another in the radial direction. These webs 12 serve to form a stator tooth 11 when the laminated core 5 is assembled. Two circumferentially adjacent webs 12 in turn delimit the groove 15 which accommodates the windings. In this design, two nozzle openings 8 are provided for each web 12.

For the radial connection of the nozzle openings 8 with the cooling channel structure 4, which is arranged radially outside the nozzle openings 8 / webs 12 in a ring body of the base body 3 that runs continuously in the circumferential direction, radially running second recesses 9b in a second sheet 10b, i.e. designed as elongated holes, serve.

Following the second sheet 10b, according to 1 and 3 a third sheet 10c is arranged, which here has only a single (third) recess 9c. The third recess 9c already forms a component of the cooling channel structure 4 and is connected in the axial direction to further recesses 9 of further sheets 10d to 10g.

With regard to the connection of the recesses 9a, 9b, 9c of the first, second and third sheets 10a, 10b, 10c with each other, in connection with the 1 , 7 and 8 It is clear that the second recesses 9b merge at their radially outer ends into a connecting channel 18 of the second sheet 10b. The connecting channel 18 here connects three second recesses 9b, which are arranged adjacent to one another in the circumferential direction. Each second recess 9b is arranged in a web 12 so as to overlap in the circumferential direction with two first recesses 9a and is thus connected to them. The third recess 9c in the third sheet 10c is arranged overlapping the connecting channel 18.

With regard to the second recesses 9b, it should also be noted that these can have different widths (dimensions in the circumferential direction). In particular, the three second recesses 9b connected to a common connecting channel 18 are 7 differently designed: A second recess 9b arranged centrally in the circumferential direction between two further second recesses 9b is designed with a smaller width compared to the other second recesses 9b.

The other sheets 10d to 10g are in connection with the 3 to 6 clearly visible. The recesses 9 of the fourth to sixth sheets 10d, 10e, 10f are designed and arranged axially adjacent to one another in such a way that they collectively form a meandering wave region 13 of the cooling channel structure 4. During operation, hydraulic fluid is guided through the wave region 13 through the annular region of the base body 3. This hydraulic fluid is previously supplied via the feed channel 14 and an inlet 19 in a finally arranged seventh sheet 10g via an inlet 19 provided there.

In the 9 and 10 alternative sheets 10 are illustrated which, with regard to their recesses 9 for forming the cooling channel structure 4, are designed differently from the previously described preferred embodiment.

With reference to 11 Finally, it should be pointed out that it is in principle possible to form the various recesses 9, in particular those sheets 10c to 10g forming the cooling channel structure 4, using only three punching tools S1, S2, S3 of different sizes.

In other words, the inventive solution directly integrates the meander guide and the nozzle design in the stator sheet, which significantly reduces parts costs and installation space requirements.

As in 2 As can be seen, the cooling fluid/hydraulic medium is introduced into the center of stator 2. Various sheet metal designs allow the fluid to be fed into a meander pattern at the back of the stator. The meander pattern increases the cooling effect because the fluid flows at a higher speed, resulting in better heat dissipation.

In 1 The guide is shown in detail. Here, you can see that the meander is formed by various sheet metal cuts/sheets 10. Additionally, on the side of the winding head 17, two sheets distribute the incoming oil evenly to each tooth, so that a closing sheet (first sheet 10a) creates nozzles that spray directly onto the copper windings.

As in the 3 to 7 As can be seen, the third and seventh plates 10c, 10g have only one fluid channel every 3, 5, 7, etc. teeth. This serves both for supply from the axially central inlet 19 and as a "wall" for the meander deflection.

The fourth plate 10d and the sixth plate 10f serve as deflection, forming the meander. The variant with double deflection is shown here.

Therefore, there is a long deflection channel and a through channel towards the winding head; after that, the arrangement is repeated. For a longer meander, for example, this arrangement changes (by using the sheets 10 of the 9 and 10 ).

The sixth sheet 10f has a shift of the sheet cut to implement the deflection on the opposite side.

The fifth plate 10e is responsible for the individual channels over the active length.

The second plate 10b is responsible for distributing the fluid to the individual teeth/webs 12, whereby the individual channels can have different dimensions to ensure an even distribution of the fluid.

The first sheet 10a ( 8 ), acts as an aperture and thus forms the nozzles (nozzle openings 8) that spray onto the winding head. The number and position of the nozzles can be freely selected.

11 shows an example of how the different sheets can be efficiently manufactured in reality.

12 to 15b show further alternative design options for stator 2.

List of reference symbols

1

electric machine

2

stator

3

Basic body

3a

first basic body

3b

second basic body

4

Cooling channel structure

5

Sheet metal package

6

Longitudinal axis

7a

first front side

7b

second front side

8

Nozzle opening

9

recess

9a

first recess

9b

second recess

9c

third recess

10a

first sheet

10b

second sheet

10c

third sheet

10d

fourth sheet

10e

fifth sheet

10f

sixth sheet

10g

seventh sheet

11

Stator tooth

12

web

13

Waveband

14

Feed chute

15

Groove

16

winding

17

winding head

18

connecting channel

19

inlet

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

• CN 115021439 A [0002]

Claims (9)

Electrical machine (1) for driving a motor vehicle, with a stator (2) which runs in an overall annular shape and with a cooling channel structure (4) which is introduced into an annular base body (3) of the stator (2) and which runs in a meandering shape at least in sections along the circumference, characterized in that the base body (3) is formed from a laminated core (5) and both the cooling channel structure (4) and a plurality of nozzle openings (8) which open towards an end face (7a, 7b) of the stator (2) are formed by different, hydraulically interconnected recesses (9) in individual sheets (10) of the laminated core (5). Machine (1) after Claim 1 , characterized in that a first sheet (10a) of the laminated core (5) arranged on the end face has the nozzle openings (8) which are introduced into webs (12) of this first sheet (10a) serving to form stator teeth (11). Machine (1) after Claim 2 , characterized in that for each web (12) there are several radially spaced nozzle openings (8) in the first sheet (10a). Machine (1) according to one of the Claims 1 until 3 , characterized in that a plurality of first recesses (9a) of the first sheet (10a) forming the nozzle openings (8) are connected to radially elongated second recesses (9b) of a second sheet (10b) arranged directly next to the first sheet (10a), wherein the second recesses (9b) are further connected to the cooling channel structure (4). Machine (1) according to one of the Claims 1 until 4 , characterized in that a meandering wave region (13) of the cooling channel structure (4) is formed by further recesses (9) made radially outside of stator teeth (11). Machine (1) according to one of the Claims 1 until 5 , characterized in that the base body (3) has an annular, radially outwardly open feed trough (14) which is connected to at least one recess (9c) of a sheet (10) serving as an inlet (15). Machine (1) according to one of the Claims 1 until 6 , characterized in that the stator (2) has several base bodies (3) arranged axially next to one another. Machine (1) after Claim 7 , characterized in that at least two base bodies (3) arranged at the ends are provided with nozzle openings (8), wherein the nozzle openings (8) of a first base body (3a) are axially remote from the nozzle openings (8) of a second base body (3b). Machine (1) according to one of the Claims 1 until 8 , characterized in that the recesses (9) are produced by stamping.

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