DE102021206834A1 - Rotor with an end plate with a connecting channel - Google Patents

Abstract

Rotor (1) for an electrical machine (23), comprising a laminated core (2) formed from stacked electrical laminations and having magnet pockets (3, 5) arranged therein, a plurality of magnets (6, 7), of which each of the magnet pockets (3, 5 ) at least one is used, several free spaces (8, 9), each of which is delimited by the magnets (6, 7) used in one of the magnet pockets (3. 5) and the laminated core (2), one on an axial side of the laminated core ( 2) arranged first end plate (10) and a second end plate (11) arranged on the opposite axial side of the laminated core (2) with a connecting channel which connects a first of the free spaces (8) with a second of the free spaces (9). In addition, an electric machine (23) with a rotor (1), a vehicle (22) with an electric machine (23) and a method for producing a rotor (1) are described.

Description

The invention relates to a rotor for an electric machine, an electric machine with a rotor, a vehicle with an electric machine and a method for producing a rotor.

The rotor has a laminated core formed from stacked electrical laminations (rotor core) with magnet pockets arranged therein and a plurality of magnets, of which at least one is inserted in each of the magnet pockets.

Electric machines with such a rotor are increasingly being used in electrically powered vehicles and hybrid vehicles, primarily as electric motors for driving a wheel or an axle of such a vehicle.

Such an electric motor is usually mechanically coupled to a gear for speed adjustment. In addition, the electric motor is usually electrically coupled to an inverter, which generates an AC voltage for the operation of the electric motor, for example a polyphase AC voltage, from a DC voltage supplied by a battery.

It is also possible to operate an electric machine with such a rotor as a generator for recuperating kinetic energy of a vehicle. For this purpose, the kinetic energy is first converted into electrical energy and then into chemical energy from a vehicle battery.

The rotor must ensure that the magnets maintain their position in the magnet pockets, especially at high speeds. For this purpose, it is customary to encapsulate the magnets in the magnet pockets with an encapsulating compound, so that the magnets are securely fastened or fixed in the laminated core.

However, the encapsulation is complex and it can happen that unwanted cavities or air bubbles remain in the laminated core. These affect the stability of the fixation of the magnets and can lead to an imbalance in the rotor.

The invention is therefore based on the object of specifying a rotor for an electrical machine whose magnets can be cast in a particularly simple manner, with no cavities or air bubbles remaining in the laminated core of the rotor.

In order to achieve the object, the invention provides for a rotor of the type mentioned at the outset to have a plurality of free spaces, each of which is delimited by the magnets inserted in one of the magnet pockets and the laminated core. Furthermore, the rotor has a first end plate arranged on one axial side of the laminated core and a second end plate arranged on the opposite axial side of the laminated core. The latter has a connecting channel which connects a first of the free spaces to a second of the free spaces.

The free spaces can be cast with a casting compound, as a result of which the magnets are fixed in the laminated core, in particular glued to the laminated core. Potting is a comparatively simple and inexpensive way of attaching the magnets.

Because of the connection of the first free space and the second free space through the connection channel, a continuous channel is formed. Potting compound filled into the first free space can therefore reach the second free space, which means that the second free space does not have to be filled separately. This makes potting particularly easy. In addition, when casting compound is filled into the first free space, air contained therein can escape to the outside through the connecting channel and the second free space. As a result, the two free spaces can be completely filled with casting compound without an undesirable cavity remaining.

In this way, the magnets are securely fastened and an imbalance in the rotor is also avoided. This ensures that the rotor permanently retains its magnetic properties. Consequently, trouble-free operation of the electrical machine to which the rotor belongs is ensured.

The laminated core can be formed from the electrical laminations by these being welded, glued, stamped or fastened to one another in some other way. In particular, the laminated core can have a cylindrical shape. Furthermore, each electrical lamination can have a central opening which, in the installed state, forms an axial borehole in the laminated core through which a rotor shaft of the rotor can lead. The axis of the rotor shaft or the rotor corresponds to the axial axis of the laminated core.

Furthermore, the laminated core can be composed of a plurality of laminated core segments, it being possible for one or more of the laminated core segments to be twisted relative to one or more of the other laminated core segments. To this Way, the rotational behavior of the rotor can be improved.

In addition to the rotor, the electrical machine can have a stator relative to which the rotor can rotate. The stator can have a further laminated core (stator core), which is formed from stacked electrical laminations. In addition, the stator can have windings of electrical conductors, for example as coil windings or flat wire windings. In addition, the machine can be equipped with a housing in which the rotor and the stator are accommodated, with the rotor shaft being able to protrude from the housing.

The magnets used in one of the magnet pockets are preferably lined up axially. As a result, the magnets can simply be inserted or pushed into the magnet pocket one after the other when assembling the rotor. The magnets lined up axially are referred to as “magnet stacks”. The rotor can have several such magnet stacks, each of which is arranged in a magnet pocket.

The first free space can be formed on a side surface of a magnet pocket, with the second free space being formed on an opposite side surface of the magnet pocket. This allows the magnets arranged between the two free spaces to be fixed particularly well with the encapsulation.

The two free spaces can be separated from one another by a magnet or a magnet stack. The volume of the free spaces is generally selected to be significantly smaller than the volume of the magnet stack in order to limit the amount of potting compound required to fill the free spaces.

In one embodiment of the invention, the connecting channel connects the first free space with the second free space to form a continuous channel which runs from a filling opening arranged in the first end plate to a ventilation opening arranged in the first end plate. This allows the magnets to be potted in the laminated core after the first end plate and the second end plate have been attached thereto. The channel can be U-shaped, for example.

In a further embodiment of the invention, the connecting channel has a groove running on the inside of the second end plate (facing the laminated core). The groove can be produced, for example, by milling or with an appropriately designed mold for the second end plate. On its side facing the laminated core, the connecting channel can be delimited by the laminated core.

Within the scope of the invention it can be provided that the groove runs between a magnet arranged on the second end plate and the second end plate. As a result, the casting compound flowing through the groove can pass the magnet over a short distance. To do this, the magnet must be at least partially spaced from the end plate.

In order to achieve the spacing of the magnet from the end plate, the magnet can bear against a projection which protrudes into the groove on one longitudinal side of the groove. The projection prevents the magnet from blocking the groove, thus ensuring the continuity of the connecting channel formed with the groove.

In this case, it can be provided that the groove is widened on its longitudinal side opposite the projection. With the widening, an impairment of the throughput of the groove with sealing compound by the projection is avoided.

In the rotor according to the invention, the first end plate and the second end plate can be connected to each other using clamping members. The laminated core is permanently subjected to a pretensioning force by the tensioning elements. The electrical steel sheets are thereby pressed together and an unwanted loosening of the electrical steel sheets is avoided even at high speeds.

The clamping elements are preferably designed as screws, which can each be secured with a nut on the laminated core. For this purpose, the screws are supported with screw heads on one of the end plates. As an alternative to this, the clamping elements can also be designed as threaded rods which are screwed to both sides with nuts. However, the laminated core can also be braced without screwing.

As already mentioned, the magnets of the rotor according to the invention are preferably cast with a casting compound that fills the free spaces. Normally the voids are completely filled with potting compound. However, it is also possible to only partially fill the free spaces with casting compound. An epoxy resin, a mixture of an epoxy resin and a hardener, or an adhesive, among others, can be used as the casting compound.

In addition, the invention relates to an electrical machine with a rotor of the type described Art. In addition to the rotor, the electric machine can have a stator, in relation to which the rotor can rotate. The stator can have a further laminated core (stator core), which is formed from stacked electrical laminations. In addition, the stator can have windings of electrical conductors, for example as coil windings or flat wire windings.

Furthermore, the invention relates to a vehicle with such an electric machine, which is provided for driving the vehicle. In particular, the machine can drive a wheel or an axle of the vehicle.

• - Bilden eines Blechpakets, in dem Magnettaschen angeordnet sind, aus gestapelten Elektroblechen,
• - Einsetzen mindestens eines Magneten in jede der Magnettaschen, so dass Freiräume verbleiben, die jeweils von den in eine der Magnettaschen eingesetzten Magneten und dem Blechpaket begrenzt sind,
• - Anordnen einer ersten Endplatte an einer Axialseite des Blechpakets,
• - Anordnen einer zweiten Endplatte an der gegenüberliegenden Axialseite des Blechpakets, wobei die zweite Endplatte einen Verbindungskanal aufweist, der einen ersten der Freiräume mit einem zweiten der Freiräume verbindet,
• - Verspannen der beiden Endplatten miteinander unter Verwendung von Spannelementen, und
• - Vergießen der in die Magnettaschen eingesetzten Magnete mit einer Vergussmasse, die in die Freiräume eingebracht wird.

Furthermore, the invention relates to a method for producing a rotor for an electrical machine, with the following steps:

• - Forming a laminated core, in which magnetic pockets are arranged, from stacked electrical laminations,
• - Insertion of at least one magnet in each of the magnet pockets, so that free spaces remain, which are limited by the magnets inserted in one of the magnet pockets and the laminated core,
• - arranging a first end plate on an axial side of the laminated core,
• - arranging a second end plate on the opposite axial side of the laminated core, the second end plate having a connecting channel which connects a first of the free spaces to a second of the free spaces,
• - Bracing the two end plates together using clamping elements, and
• - Potting of the magnets used in the magnetic pockets with a potting compound that is introduced into the free spaces.

In the method according to the invention, it is preferred that the casting compound flows out of the first free space through the connecting channel into the second free space.

• 1 eine perspektivische Ansicht eines Blechpakets und einer Rotorwelle eines erfindungsgemäßen Rotors,
• 2 einen Ausschnitt des in 1 gezeigten Blechpakets,
• 3 den mit Endplatten versehenen Rotor in einer Seitenansicht,
• 4 eine Schnittansicht des Rotors,
• 5 einen Ausschnitt der ersten Endplatte des Rotors,
• 6 eine perspektivische Ansicht eines Bereichs der Innenseite der zweiten Endplatte, und
• 7 ein Fahrzeug mit einer elektrischen Maschine mit dem Rotor.

The invention is explained below using an exemplary embodiment with reference to the figures. The figures are schematic representations and show:

• 1 a perspective view of a laminated core and a rotor shaft of a rotor according to the invention,
• 2 a section of the in 1 sheet metal package shown,
• 3 the rotor provided with end plates in a side view,
• 4 a sectional view of the rotor,
• 5 a section of the first end plate of the rotor,
• 6 a perspective view of a portion of the inside of the second endplate, and
• 7 a vehicle with an electric machine with the rotor.

That in the 1 and 2 The laminated core 2 shown with the rotor shaft 4 belongs to a rotor according to the invention for an electrical machine. The laminated core 2 encloses the rotor shaft 4 and is composed of electrical laminations which are stacked in the axial direction and which are stamped parts of identical design. The electrical laminations are divided into five laminated core segments, with a different number of laminated core segments or an unsegmented laminated core being usable.

A plurality of magnet pockets 3, 5 are arranged in the laminated core 2 along its circumference, each of which extends from the shown axial side of the laminated core 2 to its opposite axial side. In a magnet pocket 3, 5, several cuboid magnets 6, 7 are lined up axially, forming a magnet stack. A total of 32 such magnet stacks are accommodated in the laminated core, although a different number of magnet stacks can also be used.

The magnetic pockets 3, 5 are of different sizes. In particular, a distinction can be made between larger magnetic pockets 3 with longer axial openings and smaller magnetic pockets 5 with shorter axial openings. In the larger magnet pockets 3, larger magnets 6 with longer axial faces are lined up axially, while in the smaller magnet pockets 5 smaller magnets 7 with shorter axial faces are lined up axially.

Two adjacent, larger magnet pockets 3 are arranged symmetrically to one another with respect to a (not shown) radial axis of the laminated core 2, with the two magnet pockets 3 forming a V-shape. Likewise, two adjacent smaller magnet pockets 5 are arranged symmetrically to one another with respect to the radial axis, with the two magnet pockets 5 also forming a V-shape.

There are two free spaces 8, 9 next to each magnet stack, each of which is delimited by the magnet stack and the laminated core 2. In other words, each magnetic pocket 3, 5 has one on one Side surface of the magnetic pocket 3, 5 formed first free space 8 and on an opposite side surface of the magnetic pocket 3, 5 formed second free space 9, which are separated by a magnet stack. The first free space 8 and the second free space 9 run parallel to one another from one axial side to the opposite axial side of the laminated core 2 , the second free space 9 running radially outside of the first free space 8 .

3 shows the rotor 1 with a first end plate 10 and a second end plate 11 in a side view. The end plates 10, 11 are arranged on opposite axial sides of the laminated core 2 and are connected to one another using clamping elements. As a result, the laminated core 2 is permanently subjected to a compressive force or prestressing force. This prevents the electrical laminations of the laminated core 2 from becoming detached from one another, in particular at high speeds of the rotor 1.

4 shows a sectional view of the rotor 1. The clamping elements are designed as screws 12. FIG. Each of the eight screws 12 runs axially through the first end plate 10, the laminated core 2 and the second end plate 11. For this purpose, the end plates 10, 11 and the laminated core 2 are each provided with axial bores. The heads of the screws 12 are arranged on the first end plate 10 and on the second end plate 11 the screws 12 are screwed with nuts (not visible).

The first end plate 10 has first filling openings 13 and second filling openings 14 which are intended for filling the rotor core 2 with casting compound. In addition, a radial vent opening 15 formed in the first end plate 10 can be seen, which is used to vent the laminated core 2 when it is filled with casting compound.

5 shows an axial view of a section of the first end plate 10 of the rotor 1. The first filling opening 13 exposes two of the first free spaces 8, which belong to larger magnetic pockets 3. Furthermore, two of the first free spaces 8 that belong to smaller magnetic pockets 5 are exposed through the second filling opening 14 .

6 shows a perspective view of an area of the inside of the second end plate 11 with a plurality of grooves 16 running on the inside, which each belong to a connecting channel.

Each groove 16 has a projection 17 which protrudes into the groove 16 on a longitudinal side of the groove 16 . At each projection 17 is a magnet 6, 7, some of which are indicated by dashed lines. The projection 17 prevents the respective magnet 6, 7 from blocking the groove, which ensures that the connection channel formed with the groove 16 is continuous.

Because of the projection 17, the magnet 6, 7 is at least partially spaced from the second end plate 11, so that the groove 16 runs between the magnet 6, 7 and the second end plate 11. As a result, the casting compound flowing through the groove 16 can pass through the magnets 6 , 7 . In particular, the magnet 6 is at a distance from a groove base 18 of the groove 16 .

Furthermore, each groove 16 is widened on the longitudinal side opposite its projection 17 . With the widening, an impairment of the throughput of the groove 16 with sealing compound by the projection 17 is avoided.

7 FIG. 12 schematically shows a vehicle 22 with an electric machine 23 that is used to drive the vehicle 22 . The machine 22 has a housing 24 in which the rotor 1 according to the invention and a stator 25 which surrounds the rotor 1 are accommodated.

• Bei einem ersten Verfahrensschritt wird das Blechpaket 2, in dem die Magnettaschen 3, 5 angeordnet sind, aus gestapelten Elektroblechen zusammengesetzt.
• Bei einem zweiten Verfahrensschritt werden in jede Magnettasche 3, 5 mehrere Magnete 6, 7 eingesetzt. Insbesondere werden die Magnete 6, 7 axial aneinandergereiht, so dass sie einen Magnetstapel bilden. Neben jedem Magnetstapel verbleiben zwei Freiräume 8, 9, die jeweils von dem Magnetstapel und dem Blechpaket 2 begrenzt sind.
• Bei einem dritten Verfahrensschritt wird die erste Endplatte 10 an einer Axialseite des Blechpakets 2 angeordnet.
• Bei einem vierten Verfahrensschritt wird die zweite Endplatte 11 an der gegenüberliegenden Axialseite des Blechpakets 2 angeordnet, so dass der Verbindungskanal mit der Nut 16 gebildet wird.
• Bei einem fünften Verfahrensschritt werden die beiden Endplatten 10, 11 mit den Schrauben 12 und den zugehörigen Muttern verspannt. Der auf diese Weise komplettierte Rotor 1 wird senkrecht ausgerichtet, mit der ersten Endplatte 10 oben.
• Bei einem sechsten Verfahrensschritt werden die Magnete 6, 7 mit einer Vergussmasse vergossen, so dass die Freiräume 8, 9 mit der Vergussmasse gefüllt werden.

In the method according to the invention for manufacturing the rotor 1, the following method steps are carried out:

• In a first method step, the laminated core 2, in which the magnetic pockets 3, 5 are arranged, is assembled from stacked electrical laminations.
• In a second step, several magnets 6, 7 are inserted into each magnetic pocket 3, 5. In particular, the magnets 6, 7 are lined up axially so that they form a magnet stack. Two free spaces 8 , 9 remain next to each magnet stack, each of which is delimited by the magnet stack and the laminated core 2 .
• In a third method step, the first end plate 10 is arranged on an axial side of the laminated core 2 .
• In a fourth method step, the second end plate 11 is arranged on the opposite axial side of the laminated core 2 so that the connecting channel with the groove 16 is formed.
• In a fifth step, the two end plates 10, 11 are braced with the screws 12 and the associated nuts. The rotor 1 thus completed is oriented vertically, with the first end plate 10 at the top.
• In a sixth method step, the magnets 6, 7 are cast with a casting compound, so that the free spaces 8, 9 are filled with the casting compound.

For this purpose, a nozzle of a filling device is placed on each of the first free spaces 8 through each filling opening 13 , 14 of the first end plate 10 . Furthermore, the casting compound is pressed into the first free spaces 8 with excess pressure, so that the casting compound flows through the first free spaces 8 into the second free spaces 9 . Optionally, the casting compound can be pressed into both first free spaces 8 of a filling opening 13, 14 at the same time.

In detail, the casting compound first flows axially downwards through the first free spaces 8 to the second end plate 11. In 6 the associated direction of flow is symbolized by an arrow 21 .

The casting compound then flows horizontally through the grooves 16 up to the second free spaces 9. In 6 the associated direction of flow is symbolized by an arrow 19 .

The casting compound then flows through the second free spaces 9 axially upwards to the opposite axial side of the laminated core 2. In 6 the associated direction of flow is symbolized by an arrow 20 .

Meanwhile, air escapes from the laminated core 2, in particular from the free spaces 8, 9 and connecting channels, through the ventilation openings 15. This allows the magnets 6, 7 to be cast without bubbles, so that they are securely attached to the laminated core 2.

After casting, the casting compound is cured. In addition, the rotor shaft 4 can be guided through an axially extending central through-opening in the laminated core 2 (and corresponding openings in the end plates 10, 11), so that the laminated core 2 encloses the rotor shaft 4 or is attached thereto.

Reference List

1

rotor

2

laminated core

3

magnetic pocket

4

rotor shaft

5

magnetic pocket

6

magnet

7

magnet

8th

free space

9

free space

10

first endplate

11

second endplate

12

screw

13

filling hole

14

filling hole

15

vent hole

16

groove

17

head Start

18

groove bottom

19

Arrow

20

Arrow

21

Arrow

22

vehicle

23

electric machine

24

Housing

25

stator

Claims (14)

Rotor (1) for an electrical machine (23), comprising: - a laminated core (2) formed from stacked electrical laminations with magnetic pockets (3, 5) arranged therein, - several magnets (6, 7), at least one of which is inserted in each of the magnet pockets (3, 5), - Several free spaces (8, 9), each of which is delimited by the magnets (6, 7) inserted in one of the magnet pockets (3. 5) and the laminated core (2), - a first end plate (10) arranged on an axial side of the laminated core (2) and - A second end plate (11) arranged on the opposite axial side of the laminated core (2) and having a connecting channel which connects a first of the free spaces (8) to a second of the free spaces (9). Rotor (1) after claim 1 , wherein the first free space (8) is formed on a side surface of one of the magnetic pockets (3, 5) and the second free space (9) is formed on an opposite side surface of the magnetic pocket (3, 5). Rotor (1) after claim 1 or 2 , wherein the connecting channel connects the first free space (8) with the second free space (9) to form a continuous channel, which runs from a filling opening (13) arranged in the first end plate (10) to a ventilation opening ( 15) runs. Rotor (1) according to one of the preceding claims, in which the connection channel has a groove (16) running on the inside of the first end plate (13). Rotor (1) after claim 4 , wherein the groove (16) runs between one of the magnets (6, 7) arranged on the second end plate (11) and the second end plate (11). Rotor (1) after claim 5 , wherein the magnet (6, 7) bears against a projection (17) which protrudes into the groove (16) on a longitudinal side of the groove (16). Rotor (1) after claim 6 , wherein the groove (16) is widened on its longitudinal side opposite the projection (17). Rotor (1) according to one of claims 2 until 7 , several magnets (6, 7) being lined up axially in the magnet pocket (3, 5). Rotor (1) according to one of the preceding claims, wherein the first end plate (10) and the second end plate (11) are connected to one another using clamping elements. Rotor (1) according to one of the preceding claims, wherein the magnets (6, 7) are cast with a casting compound which fills the free spaces (8, 9) and the groove (16). Electrical machine (23) with a rotor (1) according to one of the preceding claims. Vehicle (22) with an electric machine (23). claim 11 , which is provided for driving the vehicle. Method for producing a rotor (1) for an electrical machine (23), with the following steps: - Forming a laminated core (2) in which magnetic pockets (3, 5) are arranged from stacked electrical laminations, - Insertion of at least one magnet (6, 7) in each of the magnet pockets (3, 5), with free spaces (8, 9) remaining, each of the magnets (6, 7) inserted in one of the magnet pockets (3, 5) and be limited to the laminated core (2), - arranging a first end plate (10) on an axial side of the laminated core (2), - arranging a second end plate (11) on the opposite axial side of the laminated core (2), the second end plate (11) having a connecting channel which connects a first of the free spaces (8) to a second of the free spaces (9), - Clamping the two end plates (10, 11) together using clamping elements and - Potting of the magnets (6, 7) used in the magnet pockets (3, 5) with a potting compound that is introduced into the free spaces (8, 9). procedure after Claim 13 , wherein when the magnets (6, 7) are cast, the casting compound flows out of the first free space (8) through the connecting channel into the second free space (9).

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