DE102022001864A1 - Rotor for an electrical machine, and electrical machine with a corresponding rotor - Google Patents

Abstract

The invention relates to a rotor (1) for an electrical machine (2), the rotor (1) being rotatable in relation to a rotor axis (3) and the rotor (1) having a rotor outer circumference (4), the rotor ( 1) has a plurality of bulges (5) formed on the rotor outer circumference (4) of the rotor (1), and the plurality of bulges (5) are arranged distributed on the rotor outer circumference (4) viewed in the circumferential direction. The invention also relates to an electrical machine (2).

Description

The invention relates to a rotor for an electrical machine, the rotor being rotatable in relation to a rotor axis and the rotor having a rotor outer circumference.

Furthermore, the invention relates to an electrical machine with a stator, which is designed to accommodate stator windings.

Electrically operated machines, such as three-phase machines, synchronous machines, asynchronous machines or other electrical machines, are required in particular for the e-mobility of vehicles. Electrically operated vehicles, such as hybrid vehicles, plug-in vehicles or electric vehicles, have an electric drive assembly or an electric motor. This requires an electric machine.

For example, permanent-magnet synchronous machines with internal magnets (IPMSM) are used in traction drives or electric drives in electrically operated vehicles. This type of synchronous machine has a high power and torque density. The internal magnets of this type of synchronous machine are, in particular, buried magnets.

Above all, electrical machines, in particular electrical three-phase machines, have a negative NVH ("noise vibration harshness" - noise, vibration, roughness). This is particularly unfavorable for passenger cars with an electric drive system, since this can be perceived as a nuisance, especially for the passengers.

For example, the DE 10 2016 109 584 A1 , the WO 2018/139675 A1 electrical machines in which the outer radius of the rotor has a notch or groove to optimize the magnetic flux.

Furthermore, for example, disclosed DE 10 2007 041 099 A1 that a rotor cross-section is shaped in a kind of glue, so that the magnets can be provided with a tapered outer radius under a kind of intermediate point. Here, the outer radius depends on an angle.

Also revealed the DE 10 2018 118 409 A1 , the DE 11 208 91 567 A1 and the EP 3 154 175 a rotor with a uniform outer radius which is interrupted at certain points by cuts, grooves or indentations.

One object of the present invention is therefore to create a rotor for an electrical machine with which audible or perceptible vibrations which are caused by the rotor or the electrical machine are reduced.

This object is achieved by a rotor according to patent claim 1 and an electrical machine according to patent claim 7 . Useful further developments result from the dependent patent claims.

• - mehrere am Rotoraußenumfangs des Rotors ausgebildete Auswölbungen, wobei
• - die mehreren Auswölbungen in Umfangsrichtung betrachtet am Rotoraußenumfang verteilt angeordnet sind.

One aspect of the invention relates to a rotor for an electrical machine, the rotor being rotatable in relation to a rotor axis and the rotor having a rotor outer circumference comprising:

• - A plurality of bulges formed on the rotor outer periphery of the rotor, wherein
• - Considered in the circumferential direction, the plurality of bulges are arranged distributed on the outer circumference of the rotor.

Due to the rotor according to the invention, the electric machine can be used in particular in electrically operated or electrically driven vehicles, without the driver and in particular the passengers of the vehicle being disturbed too much by audible or noticeable vibrations. In other words, the proposed rotor makes it possible to operate an electric machine that has improved NVH behavior.

NVH means "noise, vibration, harshness". This property can be used to describe audible or noticeable vibrations in motor vehicles or machines. Roughness refers to the audible as well as tactile transition range in the range from 20 Hertz to 100 Hertz. In general, the cause of NVH can be understood as the local introduction of force from a vibration source with vibration-transmitting media, such as structures in motor vehicles. The reasons for vibrations can be, for example, stick-slip effects (self-excited frictional vibrations) in the vehicle, which are either side effects of intentional friction or occur in the case of unwanted solid-body friction, leading to the emission of structure-borne noise and ultimately audible airborne noise. These NVH properties mentioned can be improved by the rotor designed according to the invention, so that the presence of different types in the electrically operated motor vehicle can be made more pleasant for the passengers.

A further aspect of the invention relates to an electrical machine with a stator, which is designed to accommodate stator windings, and a rotor according to the previous aspect or an advantageous development thereof, the rotor being rotatable about the rotor axis in relation to the stator. For example, the electrical machine can be a synchronous machine, in particular a permanent-magnet synchronous machine with internal magnets.

In particular, advantageous embodiments of the rotor are to be regarded as advantageous embodiments of the electrical machine and vice versa.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing(s). The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention.

• 1 Eine schematische Teildarstellung eines Rotors einer elektrischen Maschine;
• 2 eine schematische Darstellung eines Pols des Rotors aus 1; und
• 3 eine schematische Schnitt-Darstellung einer Auswölbung des Rotors aus 2.

The following figures show in:

• 1 A schematic partial representation of a rotor of an electrical machine;
• 2 a schematic representation of a pole of the rotor 1 ; and
• 3 a schematic sectional representation of a bulge of the rotor 2 .

Elements with the same function are provided with the same reference symbols in the figures.

the 1 shows a schematic representation of a rotor 1 for an electric machine 2. Only a partial representation of the rotor 1 or the electric machine 2 is shown here as an example. The rotor 1 is rotatable in relation to a rotor axis 3 . For example, the electric machine 2 can have a stator, which is designed to accommodate a stator winding. Thus, for example, the rotor 1 can be rotatable or rotatably mounted about the rotor axis 3 with respect to the stator.

The rotor 1 has a rotor outer circumference 4, for example. The rotor outer circumference 4 can be, for example, the rotor outer geometry or the peripheral outside of the rotor 1 . For example, the rotor 1 can consist at least in regions, in particular completely, of electrical steel sheet or of a laminated core.

For example, the rotor 1 can be used for a permanent-magnet synchronous machine.

As already mentioned at the outset, a positive NVH property or a positive NVH behavior is important for the use of the rotor 1 or the electric machine 2 in vehicles. The NVH behavior in the air gap can be improved with the aid of the rotor 1 according to the invention. In order in particular to be able to optimize the air gap of the magnetic field and thus to be able to reduce the noise of the electrical machine 2 , the rotor 1 has a plurality of bulges 5 formed on the outer circumference 4 of the rotor 1 . These multiple bulges 5 can be arranged distributed on the rotor outer circumference 4 viewed in the circumferential direction. In particular, depending on the application or area of use of the rotor 1, a predefined number of bulges 5 can be arranged on the outer circumference 4 of the rotor.

The bulges 5 are sheet metal elements of the rotor 1 that protrude from the outer circumference 4 of the rotor. In particular, the bulges 5 protrude from the rotor axis 3 or a center point of the rotor 1 . For example, the bulges 5 are at a greater distance from the rotor axis 3 than the rotor outer circumference 4 is from the rotor axis 3 or the axis of rotation.

For example, the bulges 5 can be structurally or arc-shaped.

The bulges 5 can be used, for example, to make a geometric adjustment to the outer geometry of the rotor or to the outer circumference 4 of the rotor. This is done, for example, with the help of the locally attached bulge 5 of the rotor 1 or the electrical steel sheet of the rotor 1. With the help of the bulges 5, the magnetic rotor field of the rotor 1 can be made sinusoidal. This exerts a positive NVH property on the electric machine 2 or the rotor 1 .

The air gap field of the electrical machine 2 is formed, for example, from the superposition of the rotor field and the stator field. This can be remedied with the help of the bulges 5 of the rotor outer circumference 4 at specifically locally defined points. In particular, it allows the rotor 1 of the invention, the presence of a homo gene air gap field and in particular a more homogeneous rotor field. As a result, higher field harmonics can be reduced in a targeted manner and, as a result, the NVH behavior of the electrical machine 2, in particular with buried magnets, can be improved.

In order in particular to improve the NVH behavior and the magnetic fields of the rotor 1 , a plurality of depressions 6 viewed in the circumferential direction can additionally or optionally be distributed on the rotor outer circumference 4 and spaced apart from the bulges 5 . The indentations 6 can be indentations, grooves or incisions. Depending on the area of use of the rotor 1 or the application for the electric machine 2 , a plurality of depressions 6 can also be arranged distributed on the outer circumference 4 . Contrary to the bulges 5, which protrude outwards from the rotor outer circumference 4, the depressions 6 are formed inwards. Thus, with respect to a radius r of the rotor 1, the depressions 6 each have a smaller radius with respect to the outer radius r. The bulges 5, on the other hand, have a larger radius with respect to the radius r.

Furthermore, in one exemplary embodiment, it can be provided that the indentations 6 and the bulges 5 are arranged on the rotor outer circumference 4 in such a way that at least one bulge 7 of the plurality of bulges 5 is at a predetermined distance from at least one adjacent indentation 8 of the plurality of indentations 6 . This can be done taking into account the outer radius r of the rotor 1 .

For example, in the 1 one of the possible poles or magnetic poles 9 of the rotor 1 is shown. Several pairs of permanent magnets 10 located inside the rotor are located within this pole. These pairs of permanent magnets 10, which can be designed in particular as buried magnets, can be arranged in pairs in the form of a V, ie in a V-shape. Thus, at least one pair of permanent magnets 10 forms a magnetic pole 9 of the rotor 1. Furthermore, the buried permanent magnets 10 can have magnetic flux barriers 11.

In the 2 a detailed view of one of the magnetic poles 9 of the rotor 1 is shown as an example. Here again the pairs of permanent magnets 10 are shown, which are arranged in a V-shape. In particular, the respective pairs are arranged symmetrically with respect to an axis of symmetry 11 of the magnetic pole 9 . Furthermore, the magnetic pole 9 has a pole center 12 . Furthermore, the permanent magnets 10 in magnet openings 13 (cf 1 ) included in the rotor 1. At least one pair of permanent magnets 10 forms a magnetic pole 9 of the rotor 1. Furthermore, the pairs of permanent magnets 10 can be arranged in a V-shape in such a way that they open toward the outer circumference 4 of the rotor.

In the representation of 2 For example, two pairs 14, 15 of permanent magnets 10 are shown in a V-shape. Contrary to 1 comes in which a "simple V" is represented by the permanent magnets 10 is in the 2 a "double V" using pairs 14, 15.

Furthermore, a bulge 18 of the plurality of bulges 5 can be arranged, in particular directly, on at least one side 16 or pole side of the magnetic pole 9 viewed in the circumferential direction, at least on a depression 17 which lies within the magnetic pole 9 . Thus, each pole side of the magnetic pole 9, which corresponding axis of symmetry 11 is mirrored, at least one depression 17 and one bulge 18 can be arranged directly spaced from one another. Any number of depressions 6 and bulges 5 can also be arranged per side 16 . In this case, the recess 17 and the bulge 18 arranged in relation to this recess 17 can be associated with one of the two permanent magnets 10 forming the magnetic pole 9 and can be oriented towards the pole center 12 of the magnetic pole 9 .

For example, the bulges 5 can be arranged on only one side of the depressions 6, in particular on the inside of the V-shaped pairs 14, 15 or also on both sides of the depressions 6. Thus, for example, a bulge 5 can be arranged on the left and right of a depression 6 .

For example, the bulge 18 can be arranged directly at the end of the indentation or indentation 17, so that in this case, for example, a uniform outer radius is provided only between the indentation 17 and the bulge 18. For example, a specified distance between the bulge 18 and the depression 17 can be specified. Within this distance the radius r is given.

For example, a depression 6 can be arranged with the adjacent bulge 5 of one of the permanent magnets 10 arranged in a V-shape and oriented towards the center of the pole 12 in relation to this V-shaped arrangement. In the double-V-shaped arrangement of the two pairs 14, 15, for example, the indentation 17 and the bulge 18 can be arranged on each of the "double-shaped" arranged magnets 10 of a leg of this V-shaped arrangement of the pairs 14, 15 be, so that the depression 17 is then between two permanent magnets 10 and the bulge 18 is correspondingly within a magnet 10 .

In the 3 it will now be explained or illustrated, for example, how a width b and a height or thickness d of the bulges 5 can be determined or calculated or determined. In particular, in the 3 a sectional view of the bulge 18 in FIG 2 shown as Section AA.

In a permanent-magnet synchronous machine with internally adjacent magnets (IPMSM) as an electrical machine 2, for example, a respective pole, ie pole 9 here as an example, is subdivided or divided into zones A to D, for example. This is again in the 2 illustrated.

(hier kann als Einheit Millimeter angesehen werden)The zones A to D indicate, for example, in which area the in the 2 For example, four individually shown bulges 5 (this is only to be understood as an example) can be. This can be specified as a function of the radius or rotor radius or outer radius r and the number of pole pairs p. The thickness or height d of the bulges 5 results as a function of the air gap thickness σ. The air gap thickness σ can be made up of the stator inner radius minus the rotor outer radius. For example, the following can be stated as an advantage: $$0.05\times \mathrm{\sigma }\le \text{i.e}\le 0.5\times \mathrm{\sigma }$$

(here millimeters can be seen as a unit)

The width b of the bulge 5 is specified according to the pole pairs in the following range: $$0.05\times \frac{\mathrm{\pi }\times \text{right}}{\text{P}\times 4}\le \text{B}\le 0.5\times \frac{\mathrm{\pi }\times \text{right}}{\text{P}\times 4}$$

This is now shown again resolved: $$0.0125\times \frac{\mathrm{\pi }\times \text{right}}{\text{p}}\le \text{B}\le 0.125\times \frac{\mathrm{\pi }\times \text{right}}{\text{p}}$$

The areas in which the individual bulges 5 are defined as follows and can be specified in circumferential length in mm or in the circumferential direction:

In zone B, the circumferential length U _mA can be as follows: $$0<{\text{u}}_{\text{mA}}\le 0.45\times \frac{\text{right}}{\text{P}}$$

In zone B, the following can apply: $$0.45<{\text{u}}_{\text{mB}}\le 0.82\times \frac{\text{right}}{\text{P}}$$

In zone C, the following can apply: $$0.82<{\text{u}}_{\text{mC}}\le 1.08\times \frac{\text{right}}{\text{P}}$$

In zone C, the following can apply: $$1.08\times \frac{\mathrm{right}}{\text{P}}\le {\text{u}}_{\text{mB}}\le 1.57\times \frac{\mathrm{right}}{\text{P}}$$

These examples of these zones for the perimeter lengths of zone A through B are presented by way of example only and are intended to enhance the reader's understanding. In particular, the examples or explanations, forms and units just mentioned are presented as examples for clarification or better understanding.

Reference List

1

rotor

2

electrical machine

3

rotor axis

4

rotor outer circumference

5

bulges

6

deepening

7

bulge of the multiple bulges

8th

indentation of the multiple indentations

9

magnetic pole

10

permanent magnets

11

flow barriers

12

pole center

11

axis of symmetry

13

magnet openings

14, 15

V-shaped pairs of permanent magnets

16

side or pole side

17

deepening of the polar side

18

bulging of the pole side

19

axis of symmetry

A to D

zones

right

radius

b

width of a bulge

i.e

height of a bulge

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely 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

• DE 102016109584 A1 [0006]
• WO 2018/139675 A1 [0006]
• DE 102007041099 A1 [0007]
• DE 102018118409 A1 [0008]
• DE 1120891567 A1 [0008]
• EP 3154175 [0008]

Claims (7)

Rotor (1) for an electrical machine (2), wherein the rotor (1) is rotatable in relation to a rotor axis (3) and the rotor (1) has a rotor outer circumference (4), characterized by - A plurality of bulges (5) formed on the rotor outer circumference (4) of the rotor (1), wherein - The plurality of bulges (5) viewed in the circumferential direction are distributed on the rotor outer circumference (4). Rotor (1) after claim 1 , characterized in that a plurality of depressions (6) viewed in the circumferential direction distributed on the rotor outer circumference (4) and spaced from the bulges (5) are arranged. Rotor (1) after claim 2 , characterized in that the indentations (6) and the bulges (5) are arranged on the rotor outer circumference (4) in such a way that at least one bulge (7) of the plurality of bulges (5) faces at least one adjacent indentation (8) of the plurality of indentations (6) has a predetermined distance. Rotor (1) according to one of the preceding claims, characterized by several pairs of permanent magnets (10) located inside the rotor (1), the permanent magnets (10) of each pair (14, 15) being arranged in a V-shape and facing towards the Rotor outer circumference (4) opens out, the permanent magnets (10) being accommodated in magnet openings (13) in the rotor (1). Rotor (1) after claim 2 and 4 , characterized in that at least one pair (14, 15) of the permanent magnets (10) form a magnetic pole (9) of the rotor (1) and on at least one side (16) viewed in the circumferential direction at least one depression (17) which is inside the Magnetic pole (9) is located, a bulge (18) of the plurality of bulges (5) is arranged. Rotor (1) after claim 5 , characterized in that the recess (17) and the bulge (18) arranged for this recess (17) are assigned to one of the two permanent magnets (10) forming the magnetic pole (9) and towards a pole center (12) of the magnetic pole (9). are oriented. Electrical machine (2), with - A stator, which is designed to accommodate stator windings, and - A rotor (1) according to any one of the preceding claims, wherein - the rotor (1) is rotatable with respect to the stator about the rotor axis (3).

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