DE102018211865A1 - Rotor for an electric motor, method for producing a rotor, and electric motor - Google Patents

Abstract

The invention relates to a rotor (R) for an electric motor, comprising a rotor shaft (1) and a rotor assembly (2) connected at least in a rotationally fixed manner to the rotor shaft, the rotor assembly comprising at least one rotor disk (2a, 2b, ...), wherein the rotor disk comprises at least two rotor disk segments (2 ', 2 ", ...) arranged one behind the other in the circumferential direction, which are connected to one another by connecting means (21), the rotationally fixed connection between the rotor shaft (1) and the rotor assembly (2) comprising at least one first pressure disk (3) and a second thrust washer (4), at least one thrust washer being connected at least in a rotationally fixed manner to the rotor shaft (1), the rotor assembly (2) being clamped between the thrust washers (3, 4), a method for producing a rotor , as well as an electric motor.

Description

The present invention relates to a rotor for an electric motor according to the preamble of claim 1, a method for producing a rotor according to claim 12, and an electric motor according to the preamble of claim 15.

A rotor for an electric motor, comprising a rotor shaft and a rotor package which is connected to the rotor shaft at least in a rotationally fixed manner, is known. The rotor assembly is usually composed of a number of rotor disks which are mounted one behind the other on the rotor shaft in the axial direction.

In this context, rotor disks are also known which consist of individual rotor disk segments which are connected to one another by a connecting means. These are so-called segmented rotor disks. In this construction, it is essentially provided that the rotor disk is not formed in one piece from a sheet metal, but instead consists of a plurality of rotor disk segments which are assembled to form a rotor disk. The advantage of using segmented rotor disks is the increased material utilization compared to, for example, circularly punched out rotor disks. Segmented stator or rotor elements are, for example, from the EP 2356734 A1 known.

On the other hand, this segmented configuration of the rotor disks can cause problems with the rotationally fixed connection of the rotor package to the rotor shaft. Conventional rotor packs, that is to say non-segmented ones, are generally connected to the rotor shaft in a transverse press fit, for example by means of a thermal shrink fit. This transverse compression bandage is accompanied by tensile stresses in the circumferential direction. If this method is applied to segmented rotor disks, the tensile stresses can widen the connecting means, i.e. the joints, of the rotor disk segments and thus counteract the non-positive fit of the rotor assembly on the shaft.

The object of the present invention is accordingly to propose an improved rotor, preferably to propose a rotor in which the problems outlined above do not occur or at least to a reduced extent, in particular to propose a rotor in which a reliable connection between a rotor package with segmented rotor disks and the rotor shaft can be guaranteed.

According to the invention, this object is achieved by a rotor with the features of claim 1.

Characterized in that the non-rotatable connection between the rotor shaft and the rotor package comprises at least a first pressure plate and a second pressure plate, at least one pressure plate being connected at least in a rotationally fixed manner to the rotor shaft, the rotor package being clamped between the pressure plates, a connection suitable for the transmission of torques can be established the rotor package with segmented rotor disks are provided, in which tensile stresses at the joints between the rotor disk segments are not to be expected, or at least not to an extent that is detrimental to the connection. Also advantageously, there is no thermal influence on the laminated core during joining, in comparison, for example, to a thermal cross-dressing.

Further advantageous refinements of the proposed invention result in particular from the features of the subclaims. The subjects or features of the various claims can in principle be combined with one another as desired.

In an advantageous embodiment of the invention, it can be provided, for example, that the rotor assembly comprises a number of rotor disks which are arranged one behind the other in the axial direction of the rotor shaft. In this respect, the rotor assembly can be constructed from a number of individual rotor disks. The rotor disks can be connected to one another by means of suitable connecting means.

In a further advantageous embodiment of the invention, it can be provided, for example, that the rotor shaft is passed through an opening provided in the rotor package, a circumferential gap being provided between the rotor shaft and the opening. In other words, it is preferably provided that the inner geometry of the laminated core is spaced apart from the outer diameter of the rotor shaft by a gap and that the laminated core is centered on the rotor shaft via the outer diameter of the laminated core. This is advantageous, among other things, because the shortening of the component tolerance chain reduces the costs for components, because again an accuracy can be achieved via an assembly process with an external centering device. In addition, machining of the rotor shaft under the laminated core is preferably not required. There are preferably no radial forces and no cross-bracing in the laminated core. Cooling through the gap is preferably possible.

Different advantageous variants are conceivable for attaching the pressure disk to or on the rotor shaft.

In an advantageous embodiment of the invention, it can be provided, for example, that the thrust washer is attached directly to the rotor shaft or is designed in one piece with the rotor shaft. This variant is material-saving and easy to implement in terms of production technology.

In a further advantageous embodiment of the invention, it can be provided, for example, that the thrust washer is attached to a flange or is designed in one piece with a flange, the flange being connected to the rotor shaft. In this variant, for example, different rotor shaft ends can be provided by the flange. In addition, the manufacture of the rotor shaft is simpler overall, since the flange, including the respective thrust washer, can be manufactured separately.

In a further advantageous embodiment of the invention, it can be provided, for example, that the rotor assembly, in particular the rotor disk, preferably at least one rotor disk segment, is equipped with at least one magnet, in particular a permanent magnet. Depending on the type of electrical machine, other electromagnetic components / current-carrying conductors, such as short-circuit bars or windings, can also be arranged in the rotor disks instead of magnets.

In a further advantageous embodiment of the invention, it can be provided, for example, that the rotor assembly, in particular the rotor disk, preferably at least one rotor disk segment, is equipped with at least one pocket for receiving the magnet. The bag is used to hold the magnet securely.

In a further advantageous embodiment of the invention it can be provided, for example, that the pocket is completely surrounded by the material of the rotor disk segment.

In a further advantageous embodiment of the invention, it can be provided, for example, that the pocket is open towards the rotor disc segment edge, the pocket preferably being closed by the rotor disc segment edge of the adjacent rotor disc segment.

In a further advantageous embodiment of the invention it can be provided, for example, that the pocket is open in the radial direction.

In a further advantageous embodiment of the invention, it can be provided that the rotor disk segments are connected to one another with connecting means, in particular form-fitting connecting means, preferably dovetail-shaped connecting means. This measure allows the rotor disk segments to be connected to one another in a simple manner to form a circular rotor disk.

In a further advantageous embodiment of the invention it can be provided that at least two rotor disks are arranged offset from one another. This results in a higher stability of the rotor package, similar to the offset in wall construction.

Another object of the present invention is to propose an advantageous method for producing a rotor according to the invention.

According to the invention, this object is achieved by a method having the method steps according to claim 12. Because of the remaining gap between the rotor assembly and the rotor shaft, among other things, a centering device can be used which comes into contact with the outer diameter or the outer surface of the rotor assembly. This centering device can also be addressed as an external centering device.

Another object of the present invention is to propose an improved electric motor, in particular to propose an electric motor in which a reliable connection between a rotor package with segmented rotor disks and the rotor shaft can be guaranteed.

According to the invention, this object is achieved by an electric motor with the characterizing features of claim 15.

• 1 ein erfindungsgemäßer Rotor in einer seitlichen Ansicht;
• 2 ein erfindungsgemäßer Rotor in einer geschnittenen seitlichen Ansicht;
• 2a ein erfindungsgemäßer Rotor in einer geschnittenen Ansicht von Vorne;
• 3a versetzte Anordnung der Rotorscheiben in einer ersten Konstellation;
• 3b versetzte Anordnung der Rotorscheiben in einer zweiten Konstellation;
• 4 Verbindungsmittel zwischen den Rotorscheibensegmenten (Varianten);
• 5 eine Ausführungsform einer Druckscheibe;
• 6 eine Ausführungsform einer Druckscheibe;
• 7 eine Ausführungsform einer Druckscheibe;
• 8 eine Ausführungsform einer Druckscheibe;
• 9 eine Ausführungsform einer Druckscheibe;
• 10 Anordnungsmöglichkeiten von Magneten und Taschen (Varianten);
• 11 ein Rotor mit einer Zentriereinrichtung;
• 12 ein erfindungsgemäßer Elektromotor.

Further features and advantages of the present invention will become clear from the following description of preferred exemplary embodiments with reference to the accompanying figures. Show in it

• 1 an inventive rotor in a side view;
• 2 an inventive rotor in a sectional side view;
• 2a an inventive rotor in a sectional view from the front;
• 3a staggered arrangement of the rotor disks in a first constellation;
• 3b staggered arrangement of the rotor disks in a second constellation;
• 4 Connecting means between the rotor disc segments (variants);
• 5 an embodiment of a thrust washer;
• 6 an embodiment of a thrust washer;
• 7 an embodiment of a thrust washer;
• 8th an embodiment of a thrust washer;
• 9 an embodiment of a thrust washer;
• 10 Arrangement of magnets and bags (variants);
• 11 a rotor with a centering device;
• 12 an electric motor according to the invention.

A rotor according to the invention R for an electric motor essentially comprises a rotor shaft 1 and a rotor package 2 , The rotor package 2 is basically rotationally symmetrical and accordingly has an axis of rotation L or longitudinal axis in the axial direction. The rotor package is along this longitudinal axis 2 with an opening 8th or bore. Overall, this results for the rotor package 2 a hollow cylindrical shape.

The rotor shaft 1 is through the opening 8th inserted through and at least rotatably, preferably firmly, with the rotor assembly 2 connected. With the rotor shaft 1 it is preferably a hollow shaft.

The rotor package 2 comprises a number of substantially circular rotor disks 2a . 2 B . .. ., preferably made of sheet steel. The rotor disc thickness can be selected depending on the centrifugal force. The rotor disks 2a . 2 B . .. , are in the axial direction along the rotor shaft 1 arranged and form the rotor package 2 , The rotor disks 2 can be connected by suitable means. The rotor disks are preferred 2a . 2 B . .. , by one or more connecting means acting in the circumferential direction 22 , such as punch nubs, adhesive dots, etc. connected together. Accordingly, these lanyards 22 to ensure that the rotor disks cannot turn against each other. Adhesive fasteners also cause an axial fixation.

In addition, the rotor or the rotor package 2 with short-circuit bars 23 be equipped. The short-circuit bars preferably run in the axial direction, parallel to the axis of rotation L , A plurality of short-circuit bars are preferably arranged next to one another in the circumferential direction. The short-circuit rod is preferably a solid copper rod, which is preferably connected to the thrust washers ( 8th ) or, together with other short-circuit rod ends, forms a short-circuit ring in the circumferential direction ( 9 ).

The rotor disk as such comprises at least two, preferably a number of rotor disk segments 2 ' . 2 ' ... which are arranged one behind the other in the circumferential direction and preferably via connecting means 21 are interconnected. With the lanyards 21 it is preferably a form-fitting connection means, in particular tongue and groove connections, for example in the manner of a dovetail connection. A selection of form-fitting connections is, for example, in the DE 20 2004 005 652 U1 given. Other connection means are also conceivable, such as adhesive connection means, in particular adhesives. Numerous variations regarding the number, shape and position of the segments are conceivable.

Various constellations are also conceivable for the arrangement of the rotor disk segments in the circumferential direction. In particular, rotor disks or partial packs of rotor disks can be arranged offset from one another. In particular, there is an offset of the abutting edges between the rotor disk segments, similar to the offset in the construction of the wall. Here, the abutting edges do not lie one behind the other in the axial direction, but are arranged offset in one or more layers in relation to one another. 3 shows an example of two configurations in which the respective rotor disc segments 2 ' of the rotor disks 2a to 2d are directly offset axially one after the other ( 3a) , alternatively is in 3b shown that partial packages consisting of several rotor disks 2a . 2 B . 2c on the one hand and 2d . 2e . 2f on the other hand, are arranged offset.

The rotor package 2 is at least non-rotatable, ie via a connection to the rotor shaft suitable for the transmission of torques 1 connected.

According to the invention it is provided that the non-rotatable connection between the rotor shaft 1 and the rotor package 2 by means of an axially acting press connection, which can also be addressed as a press fit. The non-rotatable connection essentially comprises a first thrust washer 3 and a second thrust washer 4 , wherein at least one of the pressure plates, but preferably both pressure plates 3 . 4 , rotatably with the rotor shaft 1 is connected, the rotor assembly 2 between the thrust washers 3 . 4 is clamped. Depending on the shaft stiffness, the torque can be introduced via one or both thrust washers.

The thrust washers 3 . 4 exert a pressing force on the rotor package in the axial direction 2 so that an at least frictional and / or positive connection between the thrust washers 3 . 4 and the rotor package 2 and there is ultimately a connection for transmitting a torque between the rotor shaft 1 and the rotor package 2 arises. The torque is preferably transmitted from the rotor disk segments to the pressure disk. Friction can also exist between the rotor disks.

The thrust washer 3 respectively. 4 as such, they are preferably designed as a thrust washer that extends over the entire circumference. In other words, the thrust washer protrudes radially over the rotor shaft like a circumferential collar 1 out. The thrust washers 3 . 4 also fix the rotor package 2 axially. In this respect, it is preferably provided that the pressure plates 3 . 4 also axially fixed, i.e. axially immovable, with the rotor shaft 1 are connected. This also applies indirectly if, for example, a flange to be explained in more detail 10 is used.

For the thrust washer or thrust washers 3 . 4 different variants are conceivable.

In a first embodiment it can be provided that the thrust washer 3 respectively. 4 as a separate component with regard to the rotor shaft 1 is executed. The thrust washer 3 respectively. 4 is on the rotor shaft 1 pushed on and connected to it in a rotationally fixed manner by suitable means. The rotor shaft 1 usually forms the axial end (s) of the rotor.

In a further embodiment, the thrust washer 3 respectively. 4 on a flange 10 molded or molded in one piece with this. Here is the flange 10 in sections in the rotor shaft 1 be plugged in. Part of the flange 10 protrudes from the rotor shaft 1 axially protrudes and forms an axial end of the rotor. The thrust washer 3 respectively. 4 protrudes radially over the flange as usual 10 or the rotor shaft 1 out.

The aforementioned embodiments can also be used together on a rotor, that is to say the first variant at one end and the other variant at another end of the rotor.

It is also conceivable that a thrust washer is already formed in one piece with the rotor shaft. Accordingly, the second thrust washer can be configured as described above.

It is also preferably provided that a circumferential gap 7 between the rotor shaft 1 and the hole 8th of the rotor package 2 , in particular axially along the rotor shaft. The gap can also act as a space between the outer surface of the rotor shaft 1 and the inner surface of the bore 8th be addressed. In particular, it is not a transverse press fit between the rotor shaft 1 and rotor package 2 intended.

The centering of the rotor package 2 is preferably carried out over the outer surface of the rotor assembly 2 , There is a centering device for this 9 provided with the outer surface of the rotor core 2 interacts. Such a centering device is for example in the DE 10 2015 216 971 A1 described.

The rotor package 2 , especially the rotor disc 2a . 2 B . .. ., preferably at least one rotor disk segment 2 ' . 2 ' . .. , , is with at least one magnet 6 , especially permanent magnets. Bags can be used for this 5 in the rotor package 2 , especially in the rotor disc 2a . 2 B . .. ., preferably in the rotor disc segment 2 ' . 2 ' . .. , be provided, different configurations being conceivable. So the bag can 5 for example, be completely enclosed by the material of the rotor disk segment. The pocket 5 can be open towards the edge of the rotor disc segment. The pocket 5 in this case it is preferably closed by the adjacent rotor disk segment. In a further alternative or additional embodiment, the pocket can also be open radially.

Different spatial configurations are possible for the magnet, and ultimately also for the pocket, preferably rectangular or as a segment of a circle. A plurality of pockets and magnets are preferably provided in the rotor assembly or rotor disk or rotor disk segment.

1. a) Fixieren der ersten Druckscheibe 3 auf der Rotorwelle 1 bzw. dem Flansch 10 bzw. Einsetzen des Flansches 10 mit erster Druckscheibe 3 in die Rotorwelle 1
2. b) Einsetzen des Rotorpaketes 2
3. c) Durchführen der Zentrierung des Rotorpakets 2 mittels einer auf den Außendurchmesser des Rotorpaketes einwirkenden Zentriereinrichtung 9
4. d) Auffädeln der zweiten Druckscheibe 4
5. e) Komprimieren des Rotorpaketes 2 durch Zusammenschieben der Druckscheiben 3, 4
6. f) Fixieren der zweiten Druckscheibe 4

The assembly of the rotor according to the invention R preferably comprises at least the following process steps:

1. a) Fix the first thrust washer 3 on the rotor shaft 1 or the flange 10 or inserting the flange 10 with the first thrust washer 3 into the rotor shaft 1
2. b) inserting the rotor assembly 2
3. c) performing the centering of the rotor assembly 2 by means of a centering device acting on the outer diameter of the rotor assembly 9
4. d) threading the second thrust washer 4
5. e) compressing the rotor assembly 2 by pushing the thrust washers together 3 , 4th
6. f) fixing the second thrust washer 4

• - Kreisförmige Anordnung der Rotorscheibensegmente (2', 2", ...)
• - Verbinden der Rotorscheibensegmente (2', 2", ...)
• - Axiales Anordnen der Rotorscheiben (2a, 2b, 2c, ...) zu einem Rotorpaket

Further preferred method steps that take place before the rotor stack is inserted 2 be performed:

• - Circular arrangement of the rotor disc segments ( 2 ' . 2 ' . .. .)
• - connecting the rotor disc segments ( 2 ' . 2 ' . .. .)
• - Axial arrangement of the rotor disks ( 2a . 2 B . 2c . .. .) to a rotor package

It is further preferably provided that the rotor disks are arranged with an offset.

An electric motor according to the invention essentially comprises a rotor and a stator. The rotor is preferably the rotor described above.

The invention is not limited to a specific type of electric machine. The type of electrical machine can e.g. be: Permanent Magnet Synchronous Machine (PSM), asynchronous machine (ASM), direct current series machine (GRM), externally excited synchronous machine (FSM).

Devices and methods of the type described above are used, for example, in the production of electric motors for motor vehicles.

Features and details that are described in connection with the method apply, of course, also in connection with the device according to the invention and vice versa, so that with respect to the disclosure of the individual aspects of the invention, reference can always be made to one another. In addition, the method according to the invention can be carried out with the device according to the invention.

LIST OF REFERENCE NUMBERS

L

Rotation axis / longitudinal axis

R

rotor

S

stator

1

rotor shaft

2

rotor pack

2a, 2b, ...

rotor disc

2 ', 2 ", ...

Rotor disc segment

3

First thrust washer

4

Second thrust washer

5

bag

6

magnet

7

gap

8th

Opening / drilling

9

centering

10

flange

21

Connecting means (of the rotor disc segments)

22

Connecting means (of the rotor disks)

23

Shorting bar

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2356734 A1 [0003]
• DE 202004005652 U1 [0030]
• DE 102015216971 A1 [0042]

Claims (15)

Rotor (R) for an electric motor, comprising a rotor shaft (1) and a rotor assembly (2) connected at least in a rotationally fixed manner to the rotor shaft, the rotor assembly comprising at least one rotor disk (2a, 2b, ...), the rotor disk being at least two in Circumferentially arranged rotor disc segments (2 ', 2 ", ...), characterized in that the rotationally fixed connection between the rotor shaft (1) and the rotor assembly (2) comprises at least a first pressure disc (3) and a second pressure disc (4), wherein at least one thrust washer is at least rotatably connected to the rotor shaft (1), the rotor assembly (2) being clamped between the thrust washers (3, 4). Rotor after Claim 1 , characterized in that the rotor assembly (2) comprises a number of rotor disks (2a, 2b, ...) which are arranged one behind the other in the axial direction of the rotor shaft (1). Rotor according to at least one of the preceding claims, characterized in that the rotor shaft (1) is guided through an opening (8) provided in the rotor package (2), a circumferential gap (7) being provided between the rotor shaft and the opening. Rotor according to at least one of the preceding claims, characterized in that the pressure plate (3 or 4) is attached directly to the rotor shaft (1) or is designed in one piece with the rotor shaft, or in that the pressure plate (3 or 4) is mounted on a flange (10) is attached or is designed in one piece with a flange, the flange being connected to the rotor shaft (1). Rotor according to at least one of the preceding claims, characterized in that the rotor assembly (2), in particular the rotor disk (2a, 2b, ...), preferably at least one rotor disk segment (2 ', 2 ", ...), with at least one Magnet (6), in particular a permanent magnet. Rotor according to at least one of the preceding claims, characterized in that the rotor assembly (2), in particular the rotor disk (2a, 2b, ...), preferably at least one rotor disk segment (2 ', 2 ", ...), with at least one Bag (5) for receiving the magnet (6) is equipped. Rotor according to at least one of the preceding claims, characterized in that the pocket (5) is completely enclosed by the material of the rotor disc segment (2 ', 2 ", ...). Rotor according to at least one of the preceding claims, characterized in that the pocket (5) is open towards the edge of the rotor disk segment, the pocket (5) preferably being closed by the adjacent edge of the rotor disk segment of the rotor disk segment. Rotor according to at least one of the preceding claims, characterized in that the pocket (5) is open in the radial direction. Rotor according to at least one of the preceding claims, characterized in that the rotor disc segments (2 ', 2 ", ...) are connected to one another with connecting means (21), in particular positive connecting means, preferably dovetail-shaped connecting means. Rotor according to at least one of the preceding claims, characterized in that at least two rotor disks are arranged offset from one another. Method for producing a rotor (R), according to at least one of the preceding claims, in particular according to Claim 3 , characterized by at least the following process steps: - fixing the first thrust washer (3) on the rotor shaft (1) or the flange (10) or inserting the flange (10) with the first thrust washer (3) into the rotor shaft (1) - inserting of the rotor assembly (2) - performing the centering of the rotor assembly (2) by means of a centering device (9) acting on the outer diameter of the rotor assembly - threading on the second thrust washer (4) - compressing the rotor assembly (2) by pushing the thrust washers (3, 4) together - Fix the second thrust washer (4) Procedure according to Claim 12 , characterized in that the following method steps are carried out before inserting the rotor assembly (2): - circular arrangement of the rotor disk segments (2 ', 2 ", ...) - connecting the rotor disk segments (2', 2", ...) - Axial arrangement of the rotor disks (2a, 2b, 2c, ...) to form a rotor package Method according to at least one of the preceding claims, characterized in that the rotor disks are arranged with an offset. Electric motor, comprising a rotor (R) and a stator (S), characterized by a Rotor (R) according to at least one of the preceding claims.

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