DE102021212112A1 - Process for manufacturing a can for an electrical machine - Google Patents

Abstract

Method for producing a can (5) for an electric machine (1), in particular an electric machine (1) for a motor vehicle, the can (5) having a, in particular cylindrical, can main body (7), on or in the can main body (7) at least one reinforcement section (8) is formed, which brings about a local reinforcement of the can (5).

Description

The invention relates to a method for producing a can for an electric machine, in particular an electric machine for a motor vehicle, the can having a can, in particular a cylindrical, can base body.

Methods for producing cans for electrical machines, for example electrical machines for motor vehicles, are known in principle from the prior art. Such cans are arranged in the electric machine inside the stator base body in order to separate a rotor space from a stator space. For example, this allows the rotor space to be sealed off from the stator space, in particular coolant that is routed inside the stator space can be kept in the stator space and prevented from penetrating into the rotor space. For this purpose, the can is arranged in particular on the inner circumference of the stator base body or introduced into the opening of the stator, for example pressed.

Depending on how the coolant is to be routed in the electrical machine, an appropriate sealing concept is required that prevents the coolant from getting into areas where the coolant is not wanted. In particular, it is usually prevented that coolant can flow past the can, for example, can get into an intermediate space between the stator base body and the can. A compromise must always be found here, namely such that the thinnest possible canned body can be used in order to keep the separating gap between the rotor space and stator space as small as possible in order to improve the efficiency of the electrical machine. Furthermore, high pressures and high flow rates are to be realized in the coolant circuit in order to improve the cooling of the electrical machine. However, the conduction of the coolant is limited by the can body, because if a permissible pressure is exceeded, the can body can become deformed, which can potentially lead to a leak.

The invention is based on the object of specifying a method for producing a can for an electrical machine that is improved in comparison thereto.

The object is achieved by a method having the features of claim 1. Advantageous configurations are the subject matter of the dependent claims.

As described, the invention relates to a method for producing a can for an electric machine, for example an electric machine for a motor vehicle, the can having a, in particular cylindrical, can main body. The invention is based on the finding that at least one reinforcement section is formed on or in the can main body, which reinforces the can locally.

The reinforcement section allows the canned main body to be stiffened or reinforced in at least one area in which the reinforcement section is provided. Forces that act on the can, for example due to pressure, can thus be absorbed by the reinforcement section. In particular, the reinforcement section has a higher rigidity and/or strength than areas of the can main body that are adjacent to the reinforcement section. The reinforcement section can therefore also be referred to as a stiffening section. The reinforcement section is used to at least locally bring about a reinforcement of the canned main body or to locally stiffen the canned main body.

The embodiment of the reinforcement section on or in the can main body proposed according to the invention means in particular that the can or the can main body has the reinforcement section as a component thereof. The reinforcement section is thus either an integral part of the canned body or is firmly connected to the canned body. Accordingly, it is not necessary to subsequently apply a reinforcement element to the can base body in order to locally reinforce it. Instead, the reinforcement section can be formed at the same time as the can is formed, so that further process steps can be omitted.

In a preferred embodiment, the can base body is formed by a fiber base body and a matrix material, for example by an RTM process (“resin transfer molding”). The reinforcement section can also be formed by the matrix material, in which case the reinforcement section can have, for example, a different fiber material or a different arranged fiber material than the fiber base body of the can base body. It is also possible to use the same fiber material or to use a fundamentally different material for the reinforcement section, for example a metal insert. By forming the reinforcement section in the same manufacturing process, for example impregnation or injection, the reinforcement section becomes part of the Canned body and can be introduced together with the rest of the canned body as a canned into a stator opening of a stator body. As can be seen, subsequent joining of a separate reinforcement element to the can is no longer necessary.

The method can also be further developed such that the at least one reinforcement section is produced by increasing the diameter of the can in the region of the reinforcement section. In other words, the diameter of the can or of the main body of the can in the area of the reinforcement section is greater than in areas that are adjacent in the axial direction. The diameter here is understood to mean the radial expansion of the can between an inner surface and an outer surface. In principle, it is arbitrary here whether the diameter is increased radially on the outside and/or radially on the inside of the can base body. Because the reinforcement section is provided in the corresponding area on the can base body, the wall thickness of the can increases accordingly in this area. In the context of this application, the direction of the axis of rotation of a rotor of the electric machine is understood as the axial direction. Correspondingly, a direction perpendicular to the axial direction is understood as a radial direction, in particular pointing radially outwards or inwards from the axis of rotation.

According to a further configuration, the at least one reinforcement section can be formed by introducing at least one reinforcement element. The reinforcement element can also be referred to as a stiffening element. The reinforcement element can, for example, have a higher rigidity or strength than the material that surrounds the reinforcement element in the inserted state. Viewed in cross section, the reinforcing element can in principle have any shape, with rectangular cross sections being preferred. In principle, the arrangement of the reinforcing element can be chosen as desired. The reinforcement element is firmly connected to the main body of the can in particular in a manufacturing process of the main body of the can, in particular by an injection process or an impregnation process, and is therefore connected to the main body of the main can, for example under the same matrix, in particular a resin, as the fiber material of the main body.

The method can also be further developed such that the at least one reinforcement section is formed by a reinforcement element on the inner circumference of the can base body. The reinforcement element can be arranged, for example, as an insert, in particular as a metallic insert or as an insert made of fiber-reinforced plastic FRP, for example CFRP, on the inner circumference of the can base body. For example, the reinforcement element can be arranged on a core onto which the fiber base body of the can base body is drawn. If the fiber base body is then impregnated with the matrix material, the reinforcement element is also connected to the inner circumference together with the fiber material with the can base body or the reinforcement element and the fiber base body form the can base body in cast form. The fibrous base body can in particular be a tubular base body made of fibrous material, which is drawn over a core, for example a cylinder, for connection to the matrix material and is demolded from the core after completion of the can.

The at least one reinforcement section can be formed by a reinforcement element, in particular a one-part, open or multi-part, reinforcement element on the outer circumference of the can base body. The reinforcement element can, for example, be designed in one piece, with the reinforcement element being open, i.e. the reinforcement element can basically be ring-shaped, with the ring shape not being closed, in order to allow the reinforcement element to be mounted on the outer circumference of the fiber base body during production.

It is also possible to form a multi-part reinforcement element that has, for example, at least two ring segments that can be mounted on the outer circumference of the same axial position on the fiber base body. In principle, the reinforcement section can be designed analogously to the procedure described above. This means that the fiber base body can be arranged on a core and the reinforcing element for forming the reinforcement section can be arranged on the fiber base body that has been drawn up. After the subsequent impregnation of the fiber base body and the reinforcement element with the matrix material, the fiber base body and the reinforcement element are connected to one another to form the canned base body.

According to a further embodiment of the method, at least one reinforcement section can be formed by bandaging, in particular at least one tape or roving, on the outer circumference of the can base body. Bandaging is basically understood to mean the application of a fiber material as a reinforcing element. A roving is a fiber material that is strand-like and is formed from a defined number of individual fibers, in particular several thousand individual fibers. In contrast, a tape is composed of several rovings. There is fundamental freedom in how the fiber material is applied as a bandage. The number and the geometry of the turns or windings with which the bandaging is placed around the fiber base body then determines the geometry of the reinforcement section.

In principle, a fiber orientation in the fiber base body can be different from the fiber orientation in the bandaging. For example, the fiber orientation in the bandaging runs in the circumferential direction, ie 90° to the axial direction, whereas the fiber orientation in the fiber base body can enclose a defined angle, for example 30-60°. When choosing the fiber orientation of the bandaging, the direction of force to be expected in which the bandaging is to absorb forces can be determined in particular. For example, forces caused by the coolant, which act on the split tube due to the coolant being conducted under pressure, can be absorbed by the bandaging. If the fibers are aligned in the circumferential direction, the absorption of force through the bandaging is improved.

The at least one reinforcement section can also be formed by at least one fold area of the can main body or the at least one reinforcement section can be formed by at least one fold area of the can main body and introducing at least one reinforcement element into the at least one fold area. The folding area of the canned main body is brought about in particular by folding the fiber main body. For example, the fibrous base body can be folded over, rolled up, wound up or otherwise folded on the core so that it forms at least one additional layer of the fibrous base body that rests on the base layer of the fibrous base body in the radial direction.

In other words, in the area of the reinforcement section, at least two layers of the fiber base body are thus folded up as a fold area, which can then form the reinforcement section. In addition, there is the possibility of introducing at least one reinforcement element into the fold area. Any reinforcement element described above can be used as the reinforcement element, for example an insert, in particular a metallic insert, or an insert made of a fiber material, a bandage and the like alone or in any combination. The formation of the reinforcement sections can be selected as desired. It is also possible to provide more than one reinforcing section on the same can. The individual reinforcement sections can also be combined with one another as desired, for example a fold area with or without an insert can be combined with a bandage or an insert on the outer circumference or inner circumference.

The at least one reinforcement element can also be formed with at least one retaining structure, for example a pin structure or a retaining layer, which is designed to fix the reinforcement element in the axial direction. The holding structure can also include a surface treatment, for example laser structuring, sandblasting or the selection of a specific surface topology. In particular, if the reinforcement section is to be formed by an insert, this can have a holding structure which can engage in the fibrous structure of the fiber base body. For example, individual radially extending pins, which may be distributed around the circumference of the insert, are used to radially engage the fiber body. As a result, the reinforcement element can already be fixed to the fiber base body and subsequently improve fixing. Furthermore, a compensating layer can be used, which can compensate for different thermal expansions between the fiber base body and the reinforcing element. Furthermore, an adhesive layer can be used, which enables an adhesive effect between the reinforcement element and the fiber base body.

The at least one reinforcement section can also form or provide a support surface and/or a sealing surface for the stator of an electrical machine. Due to the increase in the diameter of the can in the area of the reinforcement section, a flange or an annular projection is formed in particular. This can be used as a support surface and/or sealing surface. The support surface and/or sealing surface can, for example, be essentially aligned with its surface normal in the axial direction. When the can is installed, the support surface and/or sealing surface can be in contact with an end face of the stator base body of the stator and thus achieve a sealing effect and a support effect.

The can can be made in one piece or in two parts, for example the can can have two similar or identical can main bodies which can be mounted on a stator main body from opposite directions, for example, in particular from opposite lying directions can be introduced into the stator opening of the stator body. It makes sense here to arrange a sealing element between the two basic stator bodies, which connects the two basic stator bodies to one another and seals the gap between the inside of the basic stator body and the can. It is also possible to design the can in one piece, ie that the main body of the can reaches through the stator opening and can be in contact with the end faces of the main body of the stator, for example at both ends. In this case, the reinforcement element or the reinforcement section can come into contact with an end face of the stator, in particular at one end. A separate sealing element or reinforcement element can be used at the opposite end. In the two-part design, as described, the two basic stator bodies can be designed identically, so that each basic stator body has at least one reinforcement section that can be brought into contact with the basic stator body.

In addition, the invention relates to a can for an electrical machine, in particular an electrical machine for a motor vehicle, the can having an, in particular cylindrical, can main body, at least one reinforcement section being formed on or in the can main body, which is designed to locally reinforce the can to reinforce. All the advantages, details and features that have been described in relation to the method can be fully transferred to the can. In particular, such a can can be produced by the method described above. The can therefore has all the properties and features that were described in relation to the can in the method. Furthermore, the can can be part of an electrical machine, in particular an electrical machine for a motor vehicle. Such an electrical machine can be arranged in a motor vehicle and can have such a can, for example.

• 1 einen Ausschnitt eines Längsschnitts einer elektrischen Maschine, umfassend ein Spaltrohr nach einem ersten Ausführungsbeispiel;
• 2 einen Ausschnitt eines Querschnitts der elektrischen Maschine von 1;
• 3a-3c Verstärkungselemente für ein Spaltrohr nach 1, 2;
• 4 einen Ausschnitt eines Längsschnitts einer elektrischen Maschine, umfassend ein Spaltrohr nach einem zweiten Ausführungsbeispiel;
• 5 einen Ausschnitt eines Längsschnitts einer elektrischen Maschine, umfassend ein Spaltrohr nach einem dritten Ausführungsbeispiel;
• 6 eine schematische Darstellung einer Faserausrichtung in einem Spaltrohr;
• 7 einen Ausschnitt eines Längsschnitts einer elektrischen Maschine, umfassend ein Spaltrohr nach einem vierten Ausführungsbeispiel; und
• 8 einen Ausschnitt eines Längsschnitts einer elektrischen Maschine, umfassend ein Spaltrohr nach einem fünften Ausführungsbeispiel;

The invention is explained below on the basis of exemplary embodiments with reference to the figures. The figures are schematic representations and show:

• 1 a section of a longitudinal section of an electrical machine, comprising a can according to a first embodiment;
• 2 a section of a cross section of the electrical machine from 1 ;
• 3a-3c Reinforcing elements for a can 1 , 2 ;
• 4 a section of a longitudinal section of an electrical machine, comprising a can according to a second embodiment;
• 5 a detail of a longitudinal section of an electrical machine, comprising a can according to a third embodiment;
• 6 a schematic representation of a fiber alignment in a can;
• 7 a section of a longitudinal section of an electrical machine, comprising a can according to a fourth embodiment; and
• 8th a detail of a longitudinal section of an electrical machine, comprising a can according to a fifth embodiment;

1 shows a detail of an electrical machine 1 in a schematic longitudinal sectional view. The electrical machine 1 has a stator base body 2 which has a stator opening 3 which delimits a rotor space 4 . A can 5 is arranged in the stator opening 3 and separates the rotor chamber 4 from a stator chamber 6 . The separation by the can 5 takes place in particular in the radial direction, for example in such a way that everything radially inside the can 5 is part of the rotor space 4 and everything radially outside the can 5 can be part of the stator space 6 . Coolant that is routed through the stator base body 2 can therefore not get into the rotor space 4 , but is prevented from flowing into the rotor space 4 by the can 5 .

In this exemplary embodiment, the can 5 has a can main body 7 which is essentially cylindrical or cylinder-like and ultimately forms the part with which the can 5 engages in the stator opening 3 . For example, the can base body 7 is formed from a fiber base body that is impregnated with a matrix material or injected into the matrix material, in particular a resin, or impregnated with it.

The can 5 also has a reinforcement section 8 which is arranged on the can main body 7 or is formed in it, which reinforcement section 8 forms a support surface 9 . As in 1 , 2 shown, the can 5 in this exemplary embodiment rests with the reinforcement section 8 in the axial direction (relative to an axis of rotation 10) on the stator base body 2. In particular, the support surface 9 is in contact with an axial end face 11 of the stator base body 2.

This ensures that coolant flowing into the stator slots of the stator base body 2 cannot bypass the can 5 or enter an intermediate space or air gap between the can 5, in particular the can main body 7, and the inner surface of the stator base body 2. In the exemplary embodiment shown, the reinforcement section 8 is designed as a reinforcement element 12 or has one that rests against an outer circumference of the can base body 7, in particular its fiber base body. To produce the can 5, the reinforcement element 12, for example a component with greater rigidity than the fiber base body, is applied to the fiber base body, which is pulled onto a core, for example. The fiber base body and the reinforcement element 12 can then be connected to one another with the same matrix material and cured. The reinforcement element 12 can, for example, be a metallic insert or a fiber-reinforced plastic, for example a CFRP component.

The reinforcement section 8 forms a flange or projection in the radial direction with respect to the axis of rotation 10. The projection continues in the circumferential direction. In other words, the reinforcement section 8 widens the can 5 in the radial direction. The support surface 9 thus forms an abutment for the stator base body 2. The reinforcement section 8 can alternatively be arranged at any other point of the can 5.

As already described, the reinforcement section 8 can be formed on the canned main body 7, in particular can be designed integrally with it. The same manufacturing process can be used for this, for example. Since the can base body 7, as described, has a fiber base body that can be impregnated with a matrix material, the reinforcement section 8 can also be made of the pure matrix material, for example, if the reinforcement element 12 is dispensed with.

3a - 3c show three possible geometries for a reinforcement element 12 to form a reinforcement section 8 in the axial direction. 3a shows a closed ring. This can be applied, for example, to the fiber base body or to the core and then cured with the fiber base body together with the matrix material. 3b shows a one-piece opened cross-section, for example a broken ring. The geometry after 3b can be used, for example, to apply the reinforcement element 12 to the outer circumference of the fiber base body that is pulled onto a core.

3c shows a cross-sectional shape for a multi-part reinforcement element 12. The multi-part reinforcement element 12 can, for example, be subsequently applied to the fiber base body. The reinforcement element 12 can also have a holding structure, which is not shown in any more detail, independently of its geometry. On the one hand, a surface treatment can be used as a holding structure, in particular laser structuring, sandblasting or the formation of a specific surface topology. Furthermore, pin structures can be used, ie peg-like or pin-like projections which engage in the fiber base body and can secure the reinforcement element 12 thereto.

4 shows an alternative embodiment of the can 5, in which the reinforcement element 12 is arranged to form the reinforcement section 8 in the area of the inner circumference of the fiber base body. As described, it is possible to arrange the reinforcement element 12 on a core onto which the fiber base body, which is tubular for example, is then pulled. After the matrix material has been injected and the matrix material has hardened, the reinforcing element 12 is an integral component of the canned basic body 7. As can be seen, the diameter of the canned basic body 7 is increased by the reinforcing section 8.

In addition, due to the increased rigidity or strength of the reinforcement section 8, the can base body 7 has increased strength in this area due to the material and geometry.

5 shows a can 5 with a reinforcement section 8 according to a further embodiment. Here, a reinforcement element 12 is used, which is formed by a bandaging. In particular, a textile material is used as the bandage, for example comprising at least one roving or one tape. The bandaging can be wound as desired in terms of its cross-sectional shape and its radial extent, for example by the number and arrangement of individual windings or rovings or suitable folding of a tape. 6 shows a schematic representation of the fiber orientation 13 in the fiber base body and the fiber orientation 14 in the reinforcement element 12 designed as a bandage, for example in 5 . In the 6 The orientation of the fibers shown and the arrangements of the reinforcing elements 12 in the previous embodiments can be combined with one another as desired. The execution of the bandaging on the inner circumference is therefore just as possible as an alignment direction of the fibers when using an insert made of fiber material, such as CFRP.

As can be seen, the fiber orientation 13 in the fiber base body is selected at a defined angle relative to the axial direction, for example 30° or 60°. The fiber orientation 14 in the reinforcement element 12 designed as a bandaging runs in the circumferential direction, i.e. substantially 90° to the axial direction.

7 shows a can 5 for an electrical machine 1 according to a further embodiment. Here, the reinforcement section 8 is formed by a folding area 15 . The folding area 15 is achieved by folding the fiber base body of the can base body 7 . For example, the fiber base body can be rolled up, wound up or folded over for this purpose. Depending on which diameter the fold area 15 is to have, the fold area 15 can have several folds of the fiber base body. As described above, the fiber base body can then be impregnated with the resin and cured to form the canned base body 7 , with the fold area 15 forming the reinforcement section 8 as an integral part of the canned base body 7 .

In the 8th shown embodiment basically corresponds to the embodiment 7 , wherein a reinforcing element 12 is additionally introduced into the fold area 15 . All previous descriptions in relation to the reinforcement element 12 are therefore based on the embodiment in 8th transferable. The reinforcement element 12 can thus be produced in particular as an insert, for example made of metal or fiber-reinforced plastic, or as a bandage.

The reinforcing section 8 can also form a sealing section which is designed to seal a gap between the can 5 and the stator base body 2 . A further sealing section or a sealing element can be introduced between the reinforcement section 8 and the stator base body 2 . For example, as described above, the reinforcement section 8 can be made from the same matrix material as the can main body 7 and can be produced in the same process.

A further sealing section can be arranged in the axial direction between the end face 11 of the stator base body 2 and the reinforcing section 8, which sealing section is made of a different material, for example. Here, in particular, another matrix material can be used or the other sealing section can be made from a pure resin, i.e. the same matrix material can be used as in the area of the reinforcement section, but no fiber material is used. In principle, the sealing section can be made softer in order to improve prestressing and sealing. The sealing section can thus provide or form a sealing surface with which the end face 11 of the stator base body 2 comes into contact in order to achieve a sealing effect.

In the one with the 1 , 5 , 7 and 8th In the exemplary embodiments illustrated, the reinforcement section 8 is in each case axially in contact with the end face 11 of the stator base body 2. Alternatively, it can be provided that the reinforcement section 8 is arranged at a distance axially from the end face 11. Such an arrangement can be implemented easily and without post-processing when manufacturing the reinforcement section 8 . The previously explained sealing function in the case of a reinforcement section 8 lying against the end face 11 is not necessary, since the reinforcement section 8 prevents the diameter of the can 5 from changing. The mutual radial contact between the stator base body 2 and the can 5 already provides a sufficient sealing effect.

All the advantages, details and features shown in the individual exemplary embodiments can be combined with one another as desired, are interchangeable with one another and can be transferred to one another. The cans 5 shown can be produced using the method described herein. The electrical machine 1 can be part of a motor vehicle and can include such a can 5 .

Reference List

1

electric machine

2

stator body

3

stator opening

4

rotor space

5

cracking tube

6

stator space

7

can body

8th

reinforcement section

9

support surface

10

axis of rotation

11

face

12

reinforcement element

13, 14

fiber alignment

15

folding area

Claims (11)

Method for producing a can (5) for an electrical machine (1), in particular an electrical machine (1) for a motor vehicle, the can (5) having an, in particular cylindrical, can main body (7), characterized in that on or at least one reinforcement section (8) is formed in the can base body (7), which reinforces the can (5) locally. procedure after claim 1 , characterized in that the at least one reinforcement section (8) is produced by increasing the diameter of the can (5) in the region of the reinforcement section (8). procedure after claim 1 or 2 , characterized in that the at least one reinforcement section (8) is formed by introducing at least one reinforcement element (12). procedure after claim 3 , characterized in that the at least one reinforcement section (8) is formed by a reinforcement element (12) on the inner circumference of the can base body (7). procedure after claim 3 or 4 , characterized in that the at least one reinforcement section (8) is formed by a reinforcement element (12), in particular a one-piece, open or multi-piece, on the outer circumference of the can base body (7). procedure after claim 3 or 4 , characterized in that the at least one reinforcement section (8) is formed by a bandage, in particular at least one tape or roving, on the outer circumference of the can base body (7). Method according to one of the preceding claims, characterized in that the at least one reinforcement section (8) is formed by at least one fold area (15) of the can base body (7) or that the at least one reinforcement section (8) is formed by at least one fold area (15) of the can base body (7) and introducing at least one reinforcement element (12) into the at least one fold region (15). Method according to one of the preceding claims, characterized in that the at least one reinforcement element (12) is formed with at least one retaining structure, in particular a pin structure or a retaining layer, which is designed to fix the reinforcement element (12) in the axial direction. Method according to one of the preceding claims, characterized in that the at least one reinforcement section (8) provides a support surface and/or sealing surface for the stator of an electrical machine (1). Can (5) for an electric machine (1), in particular an electric machine (1) for a motor vehicle, the can (5) having an in particular cylindrical canned basic body (7), characterized in that on or in the canned basic body ( 7) at least one reinforcement section (8) is formed, which is designed to reinforce the can (5) locally. Electrical machine (1), which according to claim 10 trained can (5) includes.

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