DE102024200332A1 - Rotor for an electrical machine, an electrical machine, and method for producing such a rotor - Google Patents

Abstract

Rotor (10) for an electrical machine (12), electrical machine (12), and method for producing such a rotor (10), with a base body (14) which is designed as a cylindrical hollow body (15) made of magnetically conductive material, and a plurality of rotor magnets (20) resting on the radially outer circumference (16) of the base body (14), wherein the rotor magnets (20) are fastened to the base body (14) by means of sheet metal laminations (22) which extend in a ring shape around the base body (14), and the rotor magnets (20) are arranged in magnetic pockets (24) of the sheet metal laminations (22) which are closed radially outwards and are pressed radially inwards against the base body (14).

Description

The invention relates to a rotor for an electrical machine, as well as to an electrical machine and to a method for producing such a rotor according to the preamble of the independent claims.

State of the art

With the DE 10 2007 029 719 A1 A rotor of an electrical machine has become known in which "buried magnets" are arranged in radially outwardly closed magnetic pockets of the rotor. The magnetic poles of the rotor are determined by the shape of the radially outer tangential web, which radially closes off the magnetic pocket of the rotor base body. In the rotor base body, recesses are punched radially within the magnetic pockets in the sheet metal laminations of the rotor to reduce weight. However, this design requires a great deal of sheet metal material, resulting in significant waste, to manufacture the rotor.

With the CN 104659941 A Another rotor has become known in which the magnets are positioned on the surface of the rotor base body using radial retaining webs. A sleeve is then pushed over the magnets and pressed against the curved circumferential surface of the magnets. Even in this design with surface magnets, a large amount of material is used to form the sheet metal laminations of the rotor base body. This disadvantage is to be remedied by the solution according to the invention.

Disclosure of the invention

Advantages of the invention

The device according to the invention and the method according to the invention with the features of the independent claims have the advantage that, by designing the rotor base body as a hollow body, significant savings in sheet material can be achieved compared to a solid body made of laminations. The sheet metal laminations are arranged in a ring shape on the hollow body in the radial direction and press the rotor magnets radially against the surface of the base body. The rotor magnets are securely arranged in magnetic pockets of the sheet metal laminations and precisely positioned on the rotor base body. The magnetic pockets, which are closed radially outwards, thus also serve as splinter protection in the event of damage to the rotor magnets. By arranging the sheet metal laminations in the radial area of the rotor magnets, eddy current losses can be significantly reduced despite the use of a hollow body made of solid material.

The measures listed in the dependent claims enable advantageous refinements and improvements of the designs specified in the independent claims. If the radially outer sheet metal rings are manufactured as slinky components, the sheet metal waste during punching of the sheet metal laminations is significantly reduced. Preferably, a long sheet metal strip structured with magnetic pockets can be wound onto an auxiliary tool to produce a lamination sleeve, which is then pushed onto the hollow body. This can significantly reduce the raw material costs and the weight of the rotor.

It is particularly advantageous if the rotor magnets are cuboid-shaped with a rectangular cross-section, as these can be manufactured very cost-effectively. The rotor magnets rest flatly with a flat base surface on a corresponding flat contact surface on the circumference of the hollow body. The radial outer surface of the cuboid magnets is also flat and rests against a corresponding flat inner surface of the bridge webs of the magnetic pockets.

In a further embodiment, the cross-section of the rotor magnets can advantageously be designed transversely to the axial direction in the shape of a "loaf of bread," in which the curved radial outer surface is connected to the flat radial base surface by means of two tangentially opposite side surfaces. The side surfaces preferably run approximately perpendicular to the base surface, but can alternatively also extend approximately radially to the base body. Recesses are preferably punched out of the sheet metal laminations laterally of the two tangential sides of the rotor magnets in order to form a magnetic flux barrier that counteracts a magnetic short circuit of the radially magnetized rotor magnets.

The radial webs of the laminations can be arranged between two adjacent rotor magnets, tangentially spaced from the tangential side surfaces of the rotor magnets, to maximize the flux barrier. Alternatively, the axial webs can have tangential extensions that act as retaining lugs on the tangential sides of the rotor magnets. The rotor magnets can be clamped between the retaining lugs of two adjacent radial webs to remain reliably positioned during operation of the electric machine.

Two adjacent radial webs are connected to each other by a tangential connecting web on the radial outer circumference of the laminations to form a magnetic pocket for the rotor magnets. The radial outer contour of the connecting web can be circular, or it can have a sinusoidal or Richter contour to appropriately design the magnetic field of the rotor poles. The laminations are closed over their outer circumference, so that in the simplest case, the outer circumferential surface of the laminations is precisely cylindrical.

To securely position the rotor magnets around the circumference of the hollow body, flat contact surfaces are formed along the circumferential surface of the hollow body. The rotor magnets, with their equally flat bases, rest against these surfaces. During assembly, the already magnetized rotor magnets are held to the hollow body by magnetic force. To ensure long-term, reliable positioning of the rotor magnets, corresponding retaining lugs can be advantageously formed on the radial webs of the sheet metal laminations, which press against the tangential side surfaces of the rotor magnets. To form the air pockets of the flux barriers, the retaining lugs advantageously rest only on the radially inner region of the tangential side surfaces of the magnets.

If the axial preload force of the Slinky component is not sufficient, an additional clamping sleeve can be pushed axially around it, which then presses the Slinky component with the rotor magnets radially against the surface of the hollow body.

The contact surface of the base body extends at least over the entire axial extent of the rotor magnets. Rotor shaft parts are arranged on both sides of the base body, by means of which the entire rotor can be rotatably mounted in the stator. The diameter of the rotor shaft parts is significantly smaller than the diameter of the outer circumference of the base body. It is particularly advantageous if an output element—for example, a pinion or a worm—is arranged directly on one of the rotor shaft parts, which, for example, is formed monolithically with the rotor shaft part.

According to a first embodiment, for example, the hollow body is formed monolithically at least with the first rotor shaft part, wherein a first axial cover is arranged, in particular, between the hollow body and the rotor shaft part, which axially closes the hollow body. The second, in particular axially open, end of the hollow body can then be closed with a second component, which, as a second axial cover, closes the interior of the hollow body. The second axial cover can, for example, be integrally connected to the hollow body, in particular by means of a weld seam extending around the entire circumference.

In another design, the rotor is composed of a total of three separate components, with an axial cover and the respective rotor shaft part arranged on each of the two axial sides of the base body, which is designed as a hollow tube. In this design, too, the connection can be made by means of a material fit - in particular by welding. If the axial cover is inserted axially into the hollow tube, the weld seam preferably extends in the axial direction. If, on the other hand, the axial cover is placed axially onto the end face of the hollow tube, the weld seam preferably runs in the radial direction - preferably completely in the plane perpendicular to the rotor shaft parts.

In another design, the hollow body can be manufactured from a hollow tube, both ends of which are deformed to reduce their diameter. This can be achieved, for example, by thermal plastic forming. The two rotor shaft sections with smaller diameters are monolithically connected to the central hollow tube with the larger diameter, onto which the sheet metal lamination sleeve is placed.

Since the rotor base body is designed as a hollow body, the interior of the hollow body can be used for liquid cooling of the rotor magnets. For this purpose, liquid coolant is preferably introduced into the interior through an axial bore in one of the rotor shaft parts and then distributed along the radial inner wall of the hollow body by the rotation of the hollow body. This brings the coolant radially very close to the base surface of the rotor magnets in order to cool them effectively. Furthermore, radial coolant channels are formed in the hollow body through which the coolant can be guided from the interior to the stator winding in order to cool this efficiently as well. The coolant channels are arranged along both axial sides of the rotor magnets and radially through the wall of the hollow body in the west, whereby several coolant channels can be formed distributed over the circumference. The coolant channels are aligned such that the coolant impinges directly on the winding heads of the stator winding.

To fix the rotor magnets, an axial stop is formed on the radially outer circumference of the rotor base body, which preferably extends over the entire circumference. The axial The stop is formed at least at one axial end of the contact surfaces for the rotor magnets and can, for example, be designed as a radial collar of the axial cover, which is welded to the hollow tube as a separate component. In this case, the axial cover essentially projects radially beyond the contact surface for the rotor magnets on the radially outer circumference of the hollow body.

Using solid iron material to manufacture the hollow body is significantly more cost-effective than manufacturing a rotor base from individual sheet metal laminations. The hollow iron body also acts as a magnetic return path for the rotor magnets, which are preferably magnetized in the radial direction. To balance the rotor, material can be removed directly from the hollow body, for example, from at least one of the axial sides of the hollow body. The material can be removed, in particular, by grinding or machining—preferably as a small blind hole in the axial cover of the hollow tube.

The rotor according to the invention is particularly suitable for use in an electrically commutated EC motor, in which the rotor is designed as an internal rotor motor. The rotor is arranged within a stator housing containing an electronically commutable electrical winding. The inventive fastening of the rotor magnets by means of the lamination ring ensures that the rotor magnets remain reliably positioned on the hollow body and are protected from being thrown off.

To assemble the rotor according to the invention, the rotor magnets are positioned flat on the contact surfaces of the outer circumferential surface of the hollow body made of solid iron—in particular using a special assembly mask. Since the rotor magnets are preferably already radially magnetized, they are held on the contact surfaces of the rotor base body by the magnetic force. The laminations are pre-assembled as a sleeve-shaped lamination component with inwardly open magnetic pockets and then pushed axially onto the hollow body over the rotor magnets. This allows the rotor magnets to first be positioned on the hollow body using the assembly mask and then reliably and precisely fastened to the hollow body using the lamination component. If necessary, a clamping sleeve can also be pushed axially over the radial outer surface of the lamination component to further increase the axial contact force on the rotor magnets. The lamination component can be assembled from individual annular segments, for example using form-fitting locking elements that act in the circumferential direction and are punched out of the laminations. Alternatively, the sheet metal lamination sleeve can be wound helically using the Slinky technology, whereby the Slinky component is particularly formed in one piece and, for example, has a weld seam in the axial direction.

For effective liquid cooling of the electrical machine, coolant can be introduced into the interior of the hollow body in order to wet the radial inner wall of the hollow body. This allows the rotor magnets, which lie flat against the outside of the hollow body, to be cooled very easily. At the same time, liquid channels are formed in the wall of the hollow body, which guide the coolant in a radial direction to the electrical winding of the stator. In particular, a coolant circuit can be created by collecting the coolant from the electrical winding and passing it via a heat exchanger to a coolant supply for the hollow body, which is preferably designed as axial bores in one of the rotor shaft parts.

Short description of the drawings

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

• 1 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Rotors im Querschnitt,
• 2 ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Rotors im Längsschnitt,
• 3 eine weitere Ausführungsform eines Rotors im Längsschnitt, und
• 4 schematisch nur das Slinky-Bauteil der radial äußeren Blechlamellen eines weiteren Ausführungsbeispiels.

They show:

• 1 a first embodiment of a rotor according to the invention in cross section,
• 2 a further embodiment of a rotor according to the invention in longitudinal section,
• 3 another embodiment of a rotor in longitudinal section, and
• 4 schematically only the slinky component of the radially outer sheet metal lamellas of another embodiment.

In 1 An electrical machine 12 is shown in cross-section, which has a rotor 10 with a base body 14, on the outer circumference of which 16 contact surfaces 17 are formed, against which rotor magnets 20 rest with their base surfaces 25. The base body 14 is designed as a hollow body 15, the radial inner side 58 of which is preferably cylindrical. The hollow body 15 is made, for example, of solid iron and thus acts as a magnetic return ring for the rotor magnets 20, which are designed as permanent magnets. In this embodiment, the contact surfaces 17 are designed as flat surfaces in the circumferential direction 9 and in the axial direction 8, against which the base surfaces 25 of the permanent magnets 20 rest radially over their entire surface. The rotor magnets 20 are mounted in magnet pockets 24 of sheet metal laminations 22. arranged, wherein the sheet metal laminations 22 encompass the base body 14 over its entire circumference. In the circumferential regions between the rotor magnets 20, the sheet metal laminations 22 have radial webs 28, with which the sheet metal laminations 22 are supported radially on the radially outer circumferential surface 16 of the hollow body 15. The sheet metal laminations 22 are designed to be closed over the entire circumference on their radially outer circumference 23, so that the rotor magnets 20 are "buried" in the sheet metal laminations 22. The radial webs 28 are connected to one another at the radially outer circumference 23 by means of tangential bridge webs 29, which then form the magnetic poles of the rotor 10. Two adjacent radial webs 28, together with the intermediate tangential bridge web 29, each form the magnetic pocket 24. The rotor magnets 20 are clamped, for example, in the circumferential direction 9 between two adjacent axial webs 28, with the radial webs 28 directly abutting tangentially on the two tangential sides 30 of the rotor magnets 20. Flux barriers 26 are preferably formed in the sheet metal laminations 22 on the tangential sides 30, which are intended to prevent a magnetic short circuit of the rotor magnets 20 magnetized in the radial direction 7. The flux barriers 26 are punched out of the sheet metal laminations 22, for example, as air pockets on the tangential sides 30 of the permanent magnets 20, with the air pockets preferably extending obliquely, radially outwards from the hollow body 15. The radial webs 28 rest with tangential retaining lugs 34 on the tangential sides 30 of the rotor magnets 20. The sheet metal laminations 22 are designed here using slinky technology, which means that a relatively thin sheet metal strip is wound around the hollow body 15 in the shape of a spiral staircase. A very long, thin sheet metal strip—structured with the magnetic pockets 24—can be punched out in one piece and, for example, joined to the hollow body 15 in one piece over the entire axial length 18 of the rotor magnets 20. The key advantage of this slinky technology is that far less sheet metal waste is generated than with axially stacked, ring-shaped sheet metal laminations. The rotor magnets 20 can have a rectangular cross-section transverse to the axial direction 8, or a loaf-shaped cross-section, with the tangential bridging webs 29 having a corresponding inner contour. "Bread loaf-shaped" means that the radial outer surface 21 of the rotor magnets 20 is curved, for example, approximately circular. The radial outer surface 21 is connected to the base surface 25 via the two tangential side surfaces 30, wherein the side surfaces 30 are in particular aligned approximately perpendicular to the base surface 25. Here, for example, twelve rotor magnets 20 are arranged over the entire circumference of the base body 14, each of which is separated from one another in the circumferential direction 9 by the radial webs 28.

The rotor 10 is arranged within a stator 11, which has an electrical winding 70 whose magnetic field can cause the rotor 10 to rotate. The stator 11 here has a radially outer yoke ring 74, from which stator teeth 72 extend radially inward. The electrical winding 70 is designed here, for example, as a plug-in winding 71, in which relatively rigid conductor elements are inserted into stator slots 73 between the stator teeth 72. The electrical winding 70 is preferably electronically commutable, wherein the phases of the electrical winding 70 can be interconnected in different ways. The stator 11 can be made from stator rings punched out in one piece over the entire circumference, or it can be composed of several circular ring segments 75.

2 shows a longitudinal section of a further embodiment of a rotor 10 according to the invention, in which the base body 14 is again designed as a hollow body 15. The rotor magnets 20 are again arranged on the radially outer circumference 16 of the hollow body 15, which, for example, can optionally also have a bowl-shaped base surface 25, which can then bear against circular contact surfaces 17 in the circumferential direction 9. The radial outer surface 21 of the rotor magnets 20 is again surrounded by the sheet metal laminations 22, wherein their tangential bridge webs 29 form the magnet pockets 24 for the rotor magnets 20. In this embodiment, the sheet metal laminations 22 are preferably designed as a monolithic slinky component 44 in the axial direction 8 over the entire axial extent 18 of the rotor magnets 20. Optionally, a further clamping sleeve 40 (in 2 (shown in dashed lines), which presses the Slinky component 44 with the rotor magnets 20 radially against the base body 14. This clamping sleeve 40 allows higher contact forces to be exerted on the rotor magnets 20 if this is necessary for certain requirements of the electrical machine 20.

The hollow body 15 is composed of a first part 61, a second part 62, and a third part 63. The first part 61 is designed as a cylindrical hollow tube 81, the radial outer surface 16 of which forms the contact surface 17 for the rotor magnets 20. Welded to the first axial side of the first part 61 is an axial cover 82 as the second part 62, from which a first rotor shaft part 51 extends in the axial direction 8. Welded to the second axially opposite side of the hollow tube 81 is a further axial cover 83 as the third part 63, from which a second rotor shaft part 52 extends in the axial direction 8. At the first The rotor 10 can be rotatably mounted within the stator 11 on the first rotor shaft part 51 and on the second rotor shaft part 52. The two axial covers 82, 83 of the parts 62 and 63 are connected here to the hollow tube 81 of the first part 61 by means of welds 66, which extend in the axial direction 8 in longitudinal section. A coolant supply 57 is formed on the first rotor shaft part 51 and extends in the axial direction 8 through the first axial cover 82 into the interior 60 of the hollow body 15. This allows coolant 56 to pass through the coolant supply 57 into the interior 60 and wet the radial inner side 58 of the hollow body 15. The coolant 56 passes through coolant channels 55 in the hollow body 15, from the interior 60 to the stator 11, where, in particular, the electrical winding 70 can be cooled by the liquid coolant 56. The coolant channels 55 are formed here in the hollow tube 81 of the first part 61 and run in the radial direction 7 at the axial ends of the rotor magnets 20, so that the coolant 56 can preferably be guided to the winding heads of the electrical winding 70, which protrude axially from the stator slots 73. Due to the rotation of the rotor 10, the coolant 56 is guided, on the one hand, to the radial inner side 58 of the hollow body 15 for cooling the rotor magnets 20. Furthermore, the coolant 56 is guided by the centrifugal force through the coolant channels 55 directly to the electrical winding 70 of the stator 11, and is thereby supplied to a liquid cooling circuit of the electrical machine 12.

In 3 A further embodiment of a rotor 10 is shown in longitudinal section. Here, the first part 61, which is designed as a hollow tube 81, is integral with the axial cover 82 of the part 62 according to the 2 The axial cover 82 on the left side of the hollow tube 81 is funnel-shaped and merges directly into the first rotor shaft part 51, which - as in 2 - has a central coolant supply 57 to the interior 60. The axial cover 83 on the right side of the hollow tube 81 is correspondingly 2 formed as a separate component 63 that is welded to the hollow tube 81. In this embodiment, the weld seam 66 runs in the longitudinal section in the radial direction 7, and ends radially at the contact surface 17 for the rotor magnets 20. The weld seam 66 extends over the entire circumference so that the axial cover of the right cover 83 is connected to the hollow tube 81 in a liquid-tight manner. An axial stop 19 for the rotor magnets 20 is formed on the base body 14 and extends over the entire circumference. This allows the rotor magnets 20 to be positioned in a defined manner on the radially outer circumference 16 of the base body 14 with respect to the axial direction 8. 3 only the rotor magnets 20 are shown without the laminations 22, which are then shown in 4 shown. The rotor magnets 20 again lie flat against the contact surfaces 17 of the hollow body 15. Axially adjacent to the rotor magnets 20, the coolant channels 55 are formed in the hollow body 15 and extend essentially in the radial direction 7. Several coolant channels 55 can be formed over the circumference, through which the coolant 56 then escapes to the stator 11 due to the centrifugal force. An output element 54 is formed in one piece on the first rotor shaft part 51, by means of which the drive torque can be transmitted to another transmission component. Recesses 64 for balancing the rotor 10 are formed on one of the two axial covers 82, 83. These recesses can, for example, be removed by machining from the solid metal component of the hollow body 15.

For illustration purposes, 4 Only the slinky component 44 of the sheet metal laminations 22 is shown, in which a single sheet metal strip is wound in the manner of a spiral staircase over the entire axial length 18 of the rotor magnets 20. The radial webs 28 are formed on the sheet metal laminations 22 and are connected to one another in the circumferential direction 9 by means of the tangential bridge webs 29. This creates magnet pockets 24 in which the rotor magnets 20 can be accommodated. The bridge webs 29 here preferably have a flat inner surface 49, against which the flat radial outer surface 21 of cuboid rotor magnets 20 then rests. Optionally, according to the embodiment in 1 It is possible for the rotor magnets 20 to be held at their tangential side surfaces 30 between two adjacent axial webs 28 by means of the tangential retaining lugs 34, so that the sheet metal laminations 22 fix the rotor magnets 20 on the hollow body 15 in the circumferential direction. During assembly of the rotor 10, the rotor magnets 20 are preferably positioned on the surface 16 of the hollow body 15 at the contact surfaces 17 - optionally using an auxiliary tool. The sheet metal laminations 22, manufactured as a slinky component 44, are then pushed axially directly over the rotor magnets 20 onto the hollow body 15. The slinky component 44 is preferably heated and shrunk onto the hollow body. The Slinky component 44 has a radial preload, so that the sheet metal laminations 22 press the rotor magnets 20 radially against the circumferential surface 16 of the hollow body 15 due to the radial preload force. Tangential extensions 34 can be formed on the radial webs 28 as holding elements, which are pressed directly against the tangential side surfaces 30 of the rotor magnets 20. Air pockets can be cut out on the tangential side surfaces 30 of the rotor magnets 20, which then form a magnetic flux barrier 26 with respect to a magnetic form a short circuit. Alternatively, it would also be conceivable to first clamp the rotor magnets 20 into the magnet pockets 24 and then slide the Slinky component 44 with the inserted rotor magnets 20 onto the base body 14. In a further embodiment, one or more sheet metal laminations 22 with a smaller inner diameter can be arranged at an axial end of the Slinky component 44, so that they form an axial stop for the rotor magnets 20 as soon as the Slinky component 44 is completely pushed axially onto the base body 14.

To produce the slinky component 44, the structured sheet metal strip is preferably wound helically onto an auxiliary mandrel, with the planes of the sheet metal laminations 22 extending transversely to the axial direction 8 of the auxiliary mandrel. The sheet metal lamination rings are then connected to one another in the axial direction 8, for example, by welding. 4 For this purpose, for example, welding lines 46 are formed on the radial inner side 47 of the radial webs 28, or on the radial outer circumference 23 of the sheet metal laminations 22. In 1 It is shown how a notch 45 is punched out on the radial inner side 47 of the radial webs 28, in which the welding line 46 runs in the axial direction 8.

It should be noted that, with regard to the exemplary embodiments shown in the figures and in the description, a wide variety of combinations of the individual features are possible. For example, the specific design of the hollow body 15 with the contact surfaces 17, as well as the shape of the rotor magnets 20, can be varied. Likewise, the precise design of the sheet metal laminations 22, as well as the number and shape of the magnetic pockets 24 with the flux barriers 26 and/or the tangential retaining lugs 34, can be adapted to the requirements of the electrical machine 12 and its manufacturing capabilities. The elasticity—and thus the radial contact forces generated thereby—of the lamination sheet component 44 can be adjusted by the material used, its wall thickness, and the shape of the bridge webs 29. Furthermore, the liquid cooling circuit with the coolant channels 55 and the shape of the interior 60 of the hollow body 15 can be adapted to the cooling requirements of the electrical machine 12. The invention is particularly suitable for use in an EC motor designed as an internal rotor, in particular for the rotary drive of components or the adjustment of parts in a motor vehicle or as a traction drive, but is not limited to these applications.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2007 029 719 A1 [0002]
• CN 104659941 A [0003]

Claims (17)

Rotor (10) for an electrical machine (12), with a base body (14) which is designed as a cylindrical hollow body (15) made of magnetically conductive material, and a plurality of rotor magnets (20) resting on the radially outer circumference (16) of the base body (14), wherein the rotor magnets (20) are fastened to the base body (14) by means of sheet metal laminations (22) which extend in a ring-like manner around the base body (14), and the rotor magnets (20) are arranged in magnetic pockets (24) of the sheet metal laminations (22) which are closed radially outwards and are pressed radially inwards against the base body (14). Rotor (10) after Claim 1 , characterized in that the sheet metal lamellae (22) are designed as a slinky component (44) in which a long structured sheet metal strip is wound helically to form a sleeve-shaped sheet metal lamella body. Rotor (10) after Claim 1 or 2 , characterized in that the rotor magnets (20) are cuboid-shaped or bread-loaf-shaped or V-shaped and on the tangential sides (30) of the rotor magnets (20) air pockets are formed as magnetic flux barriers (26) in the sheet metal laminations (22), which extend in particular obliquely radially outwards. Rotor (10) according to one of the preceding claims, characterized in that radial webs (28) are formed on the sheet metal laminations (22), which engage radially inwards between two adjacent rotor magnets (20) - and in particular the rotor magnets (20) are clamped tangentially between the radial webs (28). Rotor (10) according to one of the preceding claims, characterized in that the sheet metal laminations (22) are formed exactly circularly on their radially outer circumference (23), or have a sinusoidal or Richter contour for forming rotor poles. Rotor (10) according to one of the preceding claims, characterized in that flat contact surfaces (17) are formed on the base body (14), against which the rotor magnets (20) lie flat - and in particular the radial webs (28) with retaining lugs (34) lie tangentially on the radially inner region of the tangential side surfaces (30) of the rotor magnets (20). Rotor (10) according to one of the preceding claims, characterized in that a clamping sleeve (40) is arranged around the sheet metal laminations (22), whereby the sheet metal laminations (22) with the rotor magnets (20) are elastically pressed radially inwards against the base body (14). Rotor (10) according to one of the preceding claims, characterized in that a rotor shaft part (51, 52) is formed on the base body (14) on both axial sides, by means of which the rotor (10) can be rotatably mounted within a stator (11) - and in particular an output element (54) for torque transmission is formed in one piece on one of the two rotor shafts (51, 52). Rotor (10) according to one of the preceding claims, characterized in that at least one of the rotor shaft parts (51, 52) is designed as a hollow shaft - and in particular is designed monolithically with the hollow body (15) of the base body (14). Rotor (10) according to one of the preceding claims, characterized in that the hollow body (15) is composed of at least two parts (61, 62, 63) which are materially connected to one another, wherein in particular a weld seam (66) between the at least two parts (61, 62) extends in the radial direction (7) or in the axial direction (8). Rotor (10) according to one of the preceding claims, characterized in that the hollow body (15) together with the two rotor shaft parts (51, 52) is manufactured monolithically from one piece, wherein the base body is designed as a hollow body (15) with a larger inner diameter than the hollow shafts of the rotor shaft parts (51, 52). Rotor (10) according to one of the preceding claims, characterized in that coolant channels (55) extend radially outwards from an interior space (60) of the hollow body (15) towards the stator (11), through which coolant channels (56) can be guided from the hollow body (15) to the stator (11) during operation. Rotor (10) according to one of the preceding claims, characterized in that an axial stop (19) for the rotor magnets (20) is formed on at least one axial side of the base body (14) on the contact surface (17) - in particular on the axial region of the weld seam (66) between the at least two parts (61, 62, 63) of the base body (14). Rotor (10) according to one of the preceding claims, characterized in that the base body (14) is made of solid iron, and on at least one axial side of the base body pers (14) recesses (64) for balancing the rotor (10) are provided. Electric machine (12) - in particular for a traction drive of a motor vehicle - with a rotor (10) according to one of the preceding claims, wherein the rotor (10) is rotatably arranged within a stator (11) having an electronically commutated winding (70). A method for producing a rotor (10) for an electrical machine (12), preferably according to one of the preceding claims, characterized by the following steps: - Providing a base body (14) of the rotor (10) designed as a hollow body (15), which is welded together, in particular, from at least two parts (61, 62, 63) - Manufacturing an annular laminar body from sheet metal laminations (22) - in particular by helically winding the radially outer sheet metal laminations (22) using the slinky technique - and axially joining the sheet metal laminations (22) to the outer circumference (16) of the base body (14) in such a way that the sheet metal laminations (22) are pressed against the base body (14) with a radial prestress - wherein preferably the rotor magnets (20) are fixed to the contact surfaces (17) of the base body (14) before the sheet metal laminations (22) are pushed onto the base body (14) with the rotor magnets (20) - Optional placement of a clamping sleeve (40) on the outer circumference (23) of the sheet metal lamellas (22). Procedure according to Claim 16 , characterized in that a coolant supply (57) is formed in at least one rotor shaft part (51, 52) so that during operation of the electrical machine (12) coolant (56) can be guided to the radial inner side (58) of the hollow body (15) and/or through the radial coolant channels (55) in the hollow body (15) to the electrical winding (70) of the stator (11).