CN115459534A

CN115459534A - Method for producing a stator

Info

Publication number: CN115459534A
Application number: CN202210628852.XA
Authority: CN
Inventors: 索斯藤·格列尔; 克里斯托夫·施姆勒林格; 萨沙·森什尼奇; 皮特·威斯克
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2021-06-08
Filing date: 2022-06-06
Publication date: 2022-12-09
Also published as: DE102021205767A1

Abstract

The invention relates to a method for producing a stator (1) having at least two stator segments (2) following one another in a circumferential direction (3), wherein the respective stator segment (2) has a coil winding (4) which is mounted on a carrier tooth (5) of the stator segment (2). Simple production of the stator (1) is achieved while increasing the power density by: the wall sections (10) are each mounted on at least two stator segments (2) following one another in the circumferential direction (3), wherein the wall sections (10) facing one another in the circumferential direction (3) form channels (12) for a cooling fluid in the stator (1). The invention also relates to such a stator (1).

Description

Method for producing a stator

Technical Field

The invention relates to a method for producing a stator of an electric machine. The invention also relates to such a stator.

Background

The stator is typically an integral part of the electrical machine and interacts with the associated rotor. In order to achieve an electromagnetic interaction with the associated rotor, at least one coil winding is usually provided at the stator. Such stators are typically constructed in the form of hollow cylinders. Here, the at least one coil winding is delimited by a radially inner wall and a radially outer wall of the coil (also known as yoke). To produce the stator, at least one coil winding is usually mounted on a hollow cylindrical carrier.

In particular in the case of stators having a larger size, in particular a larger diameter, it is also possible to use a segmented construction of the stator in order to simplify the production of the stator.

A stator of this type has a plurality of segments following one another in the circumferential direction (also referred to below as stator segments). The respective stator section usually comprises carrier teeth on which the coil windings are mounted. To produce the stator, the stator segments are arranged one behind the other in the circumferential direction and are connected to one another.

Waste heat is generated during operation of the stator, which requires cooling of the stator. For cooling the stator, a corresponding cooler can be installed at the stator. To achieve improved cooling, it is conceivable: a cooling fluid is used which absorbs heat during operation of the stator. However, this generally requires the installation of corresponding cooling channels, which leads to complex and costly manufacture of the coil.

Disclosure of Invention

The object of the invention is therefore: an improved or at least further embodiment is proposed for a method for producing a stator having at least two stator segments connected to one another and for such a stator, which is characterized by simple production and increased power density.

According to the invention, this object is achieved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

The invention is based on the following general idea: in a stator of the segmented construction, at least two of the stator segments are provided with associated segments which, in the assembled and connected state of the stator segments, form channels before the stator segments are assembled, wherein the channels can be used for cooling the stator during operation of the stator. As a result, the cooling system for cooling the stator is at least partially integrated in the manufacture of the coil sections. This results in a simplified implementation of the cooling system, in particular because the subsequent introduction of channels in or at the finished stator is eliminated or at least reduced. Furthermore, since the cooling system is integrated in the manufacture of the stator segment, the channels are arranged closer to the associated coil windings and/or the channels have an improved heat transfer connection with the coil windings. This results in improved cooling of the coil windings and thus in an increase in the power density of the stator.

According to the inventive concept, the stator therefore has at least two stator segments following one another in the circumferential direction and connected to one another. Preferably, the stator has three or more (i.e. a plurality) of such stator segments. The respective stator section comprises a carrier tooth on which the coil windings are mounted. The respective coil winding therefore has two outer sides which face away from one another in the circumferential direction. In order to produce the coil, the coil sections are arranged in the circumferential direction one behind the other, so that the outer sides of the coil windings lying behind one another are arranged opposite one another in the circumferential direction. According to the invention, before the stator sections are arranged in the circumferential direction and thus before the stator is produced, electrically insulating wall sections are respectively mounted on the side of at least two coil windings facing away from the associated carrier tooth in the circumferential direction, which coil windings are opposite to each other in the circumferential direction in the subsequent stator, so that in the subsequent stator the associated two wall sections are arranged opposite to each other between the opposite outer sides. Subsequently, the stator segments are arranged one behind the other in the circumferential direction, so that the associated wall sections each delimit a channel. For this purpose, at least one of the walls is shaped accordingly. The stator segments are then connected to each other to manufacture the stator such that the respective channels are fluid-tight with respect to the coil windings.

In practice, the stator has a hollow cylindrical shape. This means that arranging the stator segments in the circumferential direction and connecting the stator segments results in a stator which surrounds in the circumferential direction.

In principle, the stator segments can be connected in any manner. In particular, the stator segments are connected to one another in a material-fitting manner (for example by welding, in particular by ultrasonic welding).

In effect, the associated (i.e. opposite in the coil) wall portions define a cavity for constituting the channel. The cavity and thus the channel are flowable for a cooling fluid, in particular for a liquid, to cool the coil.

In principle, it is only possible to arrange such a channel and thus such a wall between two outer sides facing each other and thus between two stator segments following each other in the circumferential direction.

Such a channel is preferably formed by mounting the wall between at least two stator segments following each other in the circumferential direction, advantageously between two stator segments following each other in the circumferential direction, respectively.

In principle, the respective wall can be mounted to the associated stator segment in any manner.

Embodiments are considered to be preferred in which at least one of the walls is manufactured by injection moulding and is thus mounted at the associated stator segment. In particular, the wall is injected at the associated stator section on a side of the associated outer side of the coil winding facing away from the associated carrier tooth in the circumferential direction. Thus, a simple and defined manufacture of the wall portion is achieved, while the sealing is simplified with respect to the associated coil winding.

In principle, the material used for making the respective wall portion can be arbitrary, as long as the wall portion is electrically insulating.

In this case, an embodiment is preferred in which at least one of the wall sections, advantageously the respective wall section, is produced from a thermoplastic, in particular by injection molding. This enables a faster installation of the wall and thus a higher synchronization, in particular when producing the associated stator section.

In principle, it is possible to mount at least one of the walls directly on the outside of the associated coil winding.

Preferably, a protective layer is applied between the wall portion and the coil winding. By means of the protective layer, an improved insulation with respect to the coil winding can be achieved in particular. This means that the protective layer is mounted on the outer side of at least one of the coil windings, advantageously on the outer side of the respective coil winding, and the wall is mounted on the protective layer.

In practice, the respective protective layer is electrically insulating.

In principle, it is only possible to mount the protective layer on one or more outer sides of the associated coil winding.

Advantageously, the protective layer is mounted to the entire coil winding. Accordingly, the entire coil winding is protected accordingly.

In principle, the respective protective layer can be mounted in any desired manner on the associated coil winding.

Advantageously, at least one of the protective layers, advantageously the respective protective layer, is mounted on the coil winding by injection molding. In particular, the coil windings are overmolded with a protective layer. This enables a simple and smooth mounting of the protective layer.

In principle, the protective layer can be made of any material as long as it is electrically insulating.

Preferably, the protective layer is a thermoset. Particularly preferably, the protective layer is also attached to the coil winding by injection molding. This means that, for producing at least one protective layer, advantageously the corresponding protective layer, a thermosetting plastic is attached to the coil winding by injection molding and the coil winding is in particular overmolded with the thermosetting plastic. In this case, due to the low viscosity and thus the low injection quantity, the protective layer is applied, in particular by overmolding the coil winding with the protective layer, in order to avoid or at least reduce air pockets in the coil winding. As a result, the heat transfer from the coil windings to the cooling fluid flowing through the associated channels is improved. Furthermore, disturbances caused by cavitation are prevented or at least reduced in the operation of the coil winding.

In a particularly preferred embodiment, the protective layer is first produced by injection molding a thermosetting plastic at the coil winding. The coil windings are thus also geometrically defined and determined, which means that by subsequent wall mounting, displacements of the coil windings are prevented or at least reduced.

Subsequently, the wall part is manufactured from thermoplastic by injection moulding. Here, the presence of the previously installed protective layer achieves: the thermoplastic is injected at increased pressure and/or speed, in particular because the geometry of the coil windings is fixed by the protective layer and the protective layer also prevents air pockets in the coil windings. Thus, in general, a reliable and defined manufacture of the stator segments and thus of the stator is achieved with increased synchronicity.

In principle, the respective stator segments can have different shapes and/or be manufactured in different ways.

An embodiment in which at least two, advantageously all, of the at least two stator segments are provided as identical components and thus manufactured is preferred. This results in a particularly simple and cost-effective manufacture of the stator. At the same time, such channels are formed in this way between the coil windings of the stator sections. This results in an improved cooling and thus in an increased power density of the coil.

In order to achieve a fluid guidance through at least one channel, it is preferred that the respective channel is made at least open on one side in the axial direction. The respective channel therefore advantageously has at least one opening which is open in the axial direction for the inflow or outflow of the cooling fluid.

In an advantageous embodiment, a chamber for introducing cooling fluid or collecting cooling fluid from the corresponding channel is then arranged axially at the at least one channel, preferably also in engagement with the at least one stator segment.

In principle, the stator can be used in any application.

In particular, stators are used in electrical machines where the stator interacts with a corresponding rotor.

Furthermore, it goes without saying that stators thus manufactured fall within the scope of the present invention, in addition to methods for manufacturing stators.

Further important features and advantages of the invention emerge from the dependent claims, the figures and the associated description of the figures with reference to the figures.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively given combination but also in other combinations or alone without departing from the scope of the invention.

Drawings

Preferred embodiments of the invention are illustrated in the figures and are explained in more detail in the following description, wherein the same reference numerals indicate identical or similar or functionally identical components.

Respectively schematically showing:

figure 1 shows a top view of the stator,

figure 2 shows an isometric view during stator manufacture,

figure 3 shows a section through the stator indicated in figure 1 with III,

fig. 4 shows the view of fig. 3 in another embodiment.

Detailed Description

The stator 1 (i.e. for example the stator shown in fig. 1 to 4) comprises at least two stator segments 2 which are arranged one behind the other in the circumferential direction 3 and are connected to one another to form the stator 1. In the exemplary embodiment shown, the stator 1 has a plurality of such stator segments 2, which are arranged one behind the other in the circumferential direction 3 and are connected to one another. For this purpose, as is shown in fig. 2, the individual stator segments 2 are arranged close to one another in the circumferential direction and are subsequently connected to one another, for example in a material-fit manner, in particular by welding. As can be gathered in particular from fig. 2 to 4, the respective stator segment 2 comprises a coil winding 4, which is mounted on a carrier 5 of the stator segment 2, which carrier is also referred to below as carrier tooth 5. As can be taken from fig. 2: the stator 1 thus has the overall shape of a hollow cylinder, with the coil windings 4 of the stator segments 2 being arranged between the inner yoke 6 and the outer yoke 7. The respective carrier tooth 5 has a corresponding section of the inner yoke 6 and of the outer yoke 7. Thus, the stator 1 extends in the circumferential direction 3 and in the axial direction 9. The respective coil winding 4 has two outer sides 8 facing away from one another in the circumferential direction 3. Thus, in the stator 1, the outer sides 8 of the stator drives 2 following each other in the circumferential direction 3 are disposed opposite each other.

Fig. 3 shows a section through the stator 1 extending in the axial direction 9, which section is denoted by III in fig. 1.

From fig. 3 it can be learned that: at least two of the stator segments 2, advantageously the respective stator segment 2, are each provided with at least one wall 10 before the stator segments 2 are arranged close to one another in the circumferential direction 3, so that the walls 10 of at least two stator segments 2 following one another in the circumferential direction together delimit a cavity 11 for forming a through-flow duct 12. Such wall sections 10 are in each case mounted on the side of at least two coil windings 4 of the stator 1 which face one another in the circumferential direction 3 facing away from the associated carrier tooth 5, and then, for the production of the stator 1, the stator segments 2 are correspondingly arranged one behind the other in the circumferential direction 3 and connected to one another. The respective wall 10 thus forms a half of the associated channel 12 in the stator 1. In this case, the production of the stator 1, in particular the connection of the stator segments 2, takes place such that the respective channels 12 are fluid-tight with respect to the coil windings 4. In the exemplary embodiment shown, all stator segments 2 are provided with such a wall 10. As can be gathered from fig. 3 and 4, such a wall 10 is mounted here at the respective stator section 2 at the side of the respective coil winding 4 facing away from the associated carrier tooth 5 in the circumferential direction. As can also be gathered from fig. 3 and 4, in the exemplary embodiment shown, the stator segments 2 are produced and formed as identical components 13. For a better understanding, the wall 10 is not shown in fig. 1 and 2.

As can be gathered from fig. 3 and 4, the wall sections 10 of the illustrated embodiment are not mounted directly on the outer side 8 of the associated coil winding 4. In the exemplary embodiment shown, a protective layer 14 is provided between the outer side 8 and the respective wall 10, wherein in the exemplary embodiment shown the protective layer 14 surrounds the entire coil winding 4. The wall 10 is mounted on a protective layer 14. Here, the protective layer 14 and the wall 10 are each mounted by means of an injection molding method. The coil winding 4 is advantageously overmolded with a protective layer 14. It is furthermore advantageous to spray the wall 10 at the protective layer 14.

It is particularly preferred that the protective layer 14 be a thermoset plastic. Due to the low viscosity of the thermosetting plastic, the potting of the coil winding 4 with the thermosetting plastic forming the protective layer 14 can be carried out with a small injection quantity, so that air pockets in the coil winding 4 are avoided or at least reduced, wherein at the same time the geometry of the coil winding 4 is fixed and defined. This allows the wall 10 to be injected more quickly with a larger injection volume and higher pressure, so that the production of the respective stator section 2 can be carried out more quickly overall and with greater synchronism without damaging the coil windings 4. Particularly preferably, the wall 10 is a thermoplastic. This enables a low cost, simple and fast mounting of the wall 10.

As can be gathered from fig. 3 and 4, in this exemplary embodiment the channel 12 is open axially, and thus open in the axial direction 9. In the exemplary embodiment shown, the channel 12 is open axially on one side. Through the axial opening 15 formed by the respective channel 12, a cooling fluid, not shown, can be introduced into the respective channel 12 or can be discharged from the channel 12.

In the exemplary embodiment shown in fig. 4, the stator 1 is provided with chambers 16, which are mounted axially at the channels 12 and are in fluid connection therewith, so that, in operation, cooling fluid can flow into the respective channel 12 or out of the respective channel 12 via the chambers 16.

The stator 1 can therefore be produced simply and at low cost, wherein the cooling device of the stator 1 is integrated in the production of the stator segment 2. In addition, the cooling of the coil windings 4 is improved in this way and the power density of the stator 1 is increased.

Claims

1. A method for producing a stator (1), the stator (1) having at least two, preferably a plurality of stator segments (2) following one another in a circumferential direction (3) and connected to one another,

-wherein the respective stator segment (2) has a carrier tooth (5) on which the coil windings (4) are mounted such that the respective coil winding (5) has two outer sides (8) facing away from each other in the circumferential direction (3),

-wherein for manufacturing the stator (1) the stator segments (2) are arranged following each other in the circumferential direction (3) such that the outer sides (8) of the coil windings (4) following each other are oppositely arranged in the circumferential direction (3),

-wherein electrically insulating wall sections (10) are respectively mounted on the side of the at least two coil windings (4) opposite to each other facing away from the associated carrier tooth (5) in the circumferential direction (3) such that between the opposite outer sides (8) there are provided the associated two wall sections (10),

-subsequently arranging the stator segments (2) one after the other in the circumferential direction (3) such that the associated wall portions (10) form channels (12) respectively,

-connecting the stator segments (2) to each other such that the respective channels (12) are fluid-tight with respect to the coil windings (4).

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

at least one of the wall sections (10) is manufactured by injection moulding.

3. The method of claim 2, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

the wall (10) is produced from a thermoplastic material by injection moulding.

4. The method according to one of claims 1 to 3,

it is characterized in that the preparation method is characterized in that,

-mounting a protective layer (14) on an outer side (8) of at least one of the coil windings (4),

-mounting the wall portion (10) on a protective layer (14).

5. The method as set forth in claim 4, wherein,

it is characterized in that the preparation method is characterized in that,

the protective layer (14) is mounted to the entire coil winding (4).

6. The method according to claim 4 or 5,

it is characterized in that the preparation method is characterized in that,

the coil winding (4) is overmolded with the protective layer (14).

7. The method according to claim 5 or 6,

it is characterized in that the preparation method is characterized in that,

a thermosetting plastic is mounted as a protective layer (14) on the coil winding (4).

8. The method according to one of claims 1 to 7,

it is characterized in that the preparation method is characterized in that,

manufacturing at least two of the at least two stator segments (2) as a same component (13).

9. The method according to one of claims 1 to 8,

it is characterized in that the preparation method is characterized in that,

-making at least one of the at least one channel (12) in an open manner in the axial direction (9),

-subsequently axially arranging a chamber (16) at the channel (12) for introducing cooling fluid into the channel (12) and/or collecting cooling fluid from the channel (12).

10. A stator (1), in particular for an electrical machine, having a plurality of stator segments (2) following one another in a circumferential direction (3), wherein the stator (1) is manufactured according to a method as claimed in one of claims 1 to 9.