DE102018129897A1 - Cooling device for cooling coils of a stator of an electrical machine - Google Patents

Abstract

The invention relates to a cooling device (1) for cooling coils (11) of a stator (10) of an electrical machine, comprising: 10) and for conducting a cooling medium. Plastic and / or an electrically insulating material. The invention further relates to a stator (10) of an electrical machine with coils (11), comprising: a cooling device (1).

Description

The invention relates to a cooling device for cooling coils of a stator of an electrical machine and a stator of an electrical machine with coils and a cooling device.

Various solutions are known for cooling a stator.

For example, it is known to immerse the entire electrical machine in oil. The disadvantage of this is that there can be a considerable amount of oil in the air gap between the rotor and stator, which limits the efficiency of the electrical machine.

There are also constructions in which coolant flows on the outside of the stator stator iron to dissipate heat. However, such a solution has limited effectiveness in removing heat from the copper wires of the coils of a stator.

Furthermore, designs are known which spray cooling fluid onto the axially outer windings of the stator coils, but do not press oil into the hottest part of a stator, which is namely between two adjacent stator coils.

Furthermore, a form of cooling an electrical machine is known, in which cooling is carried out using a water jacket. The water jacket cools the stator on the outside. With the help of such a cooling, the coil windings in the vicinity of the stator are also cooled by heat conduction. The coil windings, on the other hand, which face away from the outside of the stator or are arranged on the inside of the stator (viewed in the radial direction) are cooled less well in comparison.

One way to cool the windings on the inside of the stator is to inject automatic transmission oil (ATF) from the housing of the electrical machine or from rotor nozzles.

The sprayed ATF effectively cools the windings arranged on the inside, since the sprayed ATF can soak the windings of a coil with the ATF. The windings in the active length stator slot, on the other hand, receive too little ATF from the housing or the rotor nozzles. The active length stator slot may receive some ATF from the rotor if the ATF drips into the stator-rotor air gap.

Statistically speaking, the windings of the central section of a winding head or a coil of the stator of an electrical machine form the hottest place in the electrical machine since it receives the least amount of ATF.

It is therefore an object of the present invention to provide a cooling device for cooling coils of a stator of an electrical machine and a stator of an electrical machine with coils, which cools the entire winding head of a coil of an electrical machine or the entire coil of an electrical machine and effectively dissipates heat from the space between two adjacent end windings or coils. In this context, it is also an object of the present invention to be able to push cooling liquid through and between the coils of an electrical machine without flooding the air gap of the electrical machine and reducing its efficiency.

According to the invention, these objects are achieved by the features of the independent claims. Further advantageous developments are the subject of the dependent claims.

• - mindestens einen kreisringförmigen Abschlussteil zum dichtenden Abschließen einer axialen Seite eines mit Spulen versehenen Stators und zum Leiten eines Kühlmediums.

According to the invention, in a first aspect of the present invention, a cooling device for cooling coils of a stator of an electrical machine comprises:

• - At least one annular end part for sealingly closing an axial side of a stator provided with coils and for guiding a cooling medium.

The at least one annular end part preferably has a C-shaped cross section.

The C-shaped cross section is preferably geometrically adapted to the coils of a stator. The at least one annular end part can thus be attached in a simple manner to a stator or to its coils.

The opening of the C-shaped cross section is advantageously adapted to the size of the coils of a stator, in particular to the size in the radial direction of the coils of a stator. Thus, the opening width of the C-shaped cross section can be adapted to the size of the coils, in particular in the radial direction.

Furthermore, it is favorable that the at least one end part comprises an inlet and / or outlet for a cooling medium.

It can also be provided that the at least one end part comprises at least one deflection element for deflecting a cooling medium, in particular a fluid flow.

Advantageously, the at least one deflecting element closes the C-shaped cross section of the annular closing part, so that the deflecting element prevents the flow of a cooling medium in the circumferential direction of the annular closing part and deflects the cooling medium in the axial direction.

It is also advantageous if the at least one annular end part comprises a plastic and / or an electrically insulating material.

A second aspect of the present invention includes a stator of an electrical machine.

It is expressly pointed out that the features of the cooling device, as mentioned in the first aspect, can be used individually or in combination with one another in the stator of an electrical machine.

In other words, the features relating to the cooling device mentioned above under the first aspect of the invention can also be combined here with further features under the second aspect of the invention.

A stator of an electrical machine with coils preferably comprises a cooling device according to the first aspect.

It is further preferred that the cooling device comprises two annular end parts.

It is also expedient if a terminating part is arranged, in particular fastened or locked, on an axial side of the stator and on its coils.

Advantageously, the gap, which extends in the axial direction between two adjacent coils, can be closed with a sealing element in order to prevent the escape of a cooling medium, in particular a cooling fluid.

A sealing device is preferably arranged between the coils and a closing part.

Furthermore, it is expedient for a first annular closure part to have an inlet for a cooling medium, a second annular closure part preferably having an outlet for a cooling medium.

In the following, the inventive idea presented above is additionally expressed in other words.

This idea preferably relates - to put it in simplified form - to forced cooling for windings or coils of a stator of an electrical machine, which comprises a closing part which is preferably semi-toroidal (or C-shaped in cross section).

The end part is preferably arranged on the stator or on a first axial side of the stator.

This terminating part advantageously allows a flow of a cooling medium around the windings of a coil of a stator.

The end part forces the cooling medium, in particular a cooling oil, to flow between the windings or between two adjacent coils of a stator from a first axial side of the stator to a second axial side in the axial direction.

The second axial side of the stator advantageously also comprises a closing part, which is preferably half-toroidal (or C-shaped in cross section).

In the event that a cooling medium is pumped from the first axial side through an inlet of a closing part to the second axial side, the closing part first distributes the cooling medium along the diameter of the stator and then forces the cooling medium in the axial direction between the coils of the stator stream.

As soon as the cooling medium is taken up on the second axial side by a further end part and has likewise been distributed along the diameter of the stator, this flows to the outlet of the further end part.

The inlet of the one end part is advantageously arranged diametrically to the outlet of the other end part.

Conveniently, the outlet is located higher than the surface of the earth compared to the inlet. This allows a convective flow of the cooling medium.

• 1 bis 3 eine 3-dimensionale Ansicht aus verschiedenen Blickwinkeln auf einen erfindungsgemäßen Stator einer elektrischen Maschine mit einer erfindungsgemäßen Kühlungseinrichtung nach einem ersten Ausführungsbeispiel;
• 4 eine Schnittansicht auf den erfindungsgemäßen Stator aus den 1 bis 3;
• 5 eine 3-dimensionale Ansicht eines Abschlussteils einer erfindungsgemäßen Kühlungseinrichtung nach einem zweiten Ausführungsbeispiel; und
• 6 eine schematische Darstellung des Fluidstromes eines Kühlmediums unter Verwendung der erfindungsgemäßen Kühlungseinrichtung nach dem zweiten Ausführungsbeispiel.

The invention is explained in more detail below on the basis of exemplary embodiments in conjunction with associated drawings. Here show schematically:

• 1 to 3rd a 3-dimensional view from different angles on a stator according to the invention of an electrical machine with a cooling device according to the invention according to a first embodiment;
• 4th a sectional view of the stator according to the invention from the 1 to 3rd ;
• 5 a 3-dimensional view of a closing part of a cooling device according to the invention according to a second embodiment; and
• 6 is a schematic representation of the fluid flow of a cooling medium using the cooling device according to the invention according to the second embodiment.

In the following description, the same reference symbols are used for the same objects.

1 to 3rd show a 3-dimensional view from different angles on a stator according to the invention 10th an electrical machine with a cooling device according to the invention 1 according to a first embodiment.

4th shows a sectional view of the stator according to the invention 10th from the 1 to 3rd .

For simplicity and brevity, the following are the 1 to 4th described together.

The are shown in more detail 1 to 4th a stator 10th an electrical machine with coils 11 .

Here, the stator includes 10th a cooling device 1 for cooling coils 11 of the stator 10th an electrical machine.

The cooling device 1 has, as in particular in 2nd shown, two circular end pieces 2nd , 3rd for sealing an axial side of the with coils 11 provided stator 10th and to conduct a cooling medium.

The ring-shaped end pieces 2nd , 3rd each have a C-shaped cross-section that is geometrical on the coils 11 of the stator 10th is adjusted.

In other words, the opening of the C-shaped cross section of a closing part is in each case 2nd , 3rd on the size of the coils 11 of the stator 10th , especially the size in the radial direction R of the coils 11 of the stator 10th , customized.

Furthermore shows in particular 2nd that the final part 2nd an inlet 4th for a cooling medium and the end part 3rd an outlet 5 for a cooling medium.

Each of the two circular end pieces 2nd , 3rd is on one axial side of the stator 10th and on its coils 11 arranged.

The gap 7 that is in the axial direction A between two adjacent coils 11 extends, can be closed with a sealing element in order to prevent the escape of cooling medium.

There is also a sealing device (not shown) between the coils 11 and a final part 2nd , 3rd arranged.

5 shows a 3-dimensional view of a closing part 2nd , 3rd a cooling device according to the invention 1 according to a second embodiment, wherein 6 is a schematic representation of the fluid flow of a cooling medium using the cooling device according to the invention 1 shows according to the second embodiment.

Like that 5 and 6 the end parts show 2nd , 3rd several deflection elements 6 to redirect a cooling medium.

Here, each deflecting element closes 6 the C-shaped cross section of the annular end part 2nd , 3rd , so that the deflecting element 6 a flow of a cooling medium in the circumferential direction U of the annular end part 2nd , 3rd prevents and the cooling medium in the axial direction A redirects (see in particular 6 ).

Finally, it should be mentioned that an annular end piece 2nd , 3rd comprises a plastic and / or an electrically insulating material.

Below will be 1 to 6 described again in other words.

Here show the 1 to 3rd an electrical machine with a stator which has windings of any type (concentrated or distributed winding).

In the present case, it is a stator 10th with concentrated effects.

Preferably, two adjacent coils or winding heads are over a gap 7 , which is in the axial direction A extends, separated from each other.

Within that column 7 a sealing element (not shown) is advantageously arranged, which prevents the escape of a cooling medium, in particular a cooling fluid.

On the opposite axial sides of the stator 10th is an annular end piece 2nd , 3rd arranged, which is C-shaped in cross section.

Every final part 2nd , 3rd is preferably with the coils 11 on the axial sides of the stator 10th locked.

Here, an annular end part comprises 2nd , 3rd preferably a plastic and / or an electrically insulating material.

For example, in 2nd shown that the stator 10th an inlet 4th and an outlet 5 for a cooling medium.

The inlet is advantageous 4th arranged underneath, whereas the outlet 5 is arranged on the top. In this way, the flow of cooling medium can be facilitated, since heated cooling medium has a lower density than a comparison of cooler cooling medium.

The heat transfer through the cooling medium is convective and the cooling medium moves through the end part 2nd , 3rd .

How in particular 5 and 6 can be seen in each end part 2nd , 3rd Deflecting elements 6 have through which the cooling medium is moved between the coil windings.

The deflection elements 6 also ensure that the cooling medium touches the entire winding area of a coil to cool it down.

Reference symbol list

1

Cooling device

2nd

Final part

3rd

Final part

4th

inlet

5

Outlet

6

Deflecting element

7

gap

10th

stator

11

Kitchen sink

A

axial direction

R

radial direction

U

Circumferential direction

Claims (4)

Cooling device (1) for cooling coils (11) of a stator (10) of an electrical machine, comprising: - At least one annular end part (2, 3) for sealingly sealing an axial side of a stator (10) provided with coils (11) and for guiding a cooling medium. Cooling device after Claim 1 , - wherein the at least one annular end part (2, 3) comprises a C-shaped cross-section, - preferably the C-shaped cross-section is geometrically adapted to the coils (11) of a stator (10), - preferably the opening of the C -shaped cross-section is adapted to the size of the coils (11) of a stator (10), in particular to the size in the radial direction (R) of the coils (11) of a stator (10), - the at least one end part (2 , 3) comprises an inlet (4) or outlet (5) for a cooling medium. Cooling device after Claim 1 or 2nd , - wherein the at least one closing part (2, 3) comprises at least one deflecting element (6) for deflecting a cooling medium, in particular a fluid flow, - whereby preferably the at least one deflecting element (6) has the C-shaped cross section of the annular closing part (2, 3) closes, so that the deflecting element (6) prevents a flow of a cooling medium in the circumferential direction (U) of the annular end part (2, 3) and deflects the cooling medium in the axial direction (A), - preferably the at least one annular end part (2, 3) comprises a plastic and / or an electrically insulating material. Stator (10) of an electrical machine with coils (11) comprising: a cooling device (1) according to one of the preceding claims, - The cooling device (2) comprises two annular end parts (2, 3), - A respective end part (2, 3) is arranged on an axial side of the stator (10) and on its coils (11), - The gap (7), which extends in the axial direction (A) between two adjacent coils (11), can be closed with a sealing element in order to prevent the escape of a cooling medium, in particular a cooling fluid.

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