DE102017111955A1 - Cost-optimized rotor of an electric machine - Google Patents

Abstract

The invention relates to a rotor (1) for an electrical machine with a rotor laminated core (2) and magnets (3), wherein in the rotor laminated core (2) a plurality of elongated magnet receiving slots (23) for receiving a respective magnet (3) arranged in the radial direction are, wherein the outer ends of the magnet receiving slots (23) are open, wherein between two magnet receiving slots (23) in the vicinity of the radially inner end of the magnet receiving slots (23) in an axial direction through the rotor core (2) extending magnetic flux steering hole (22) is ordered. Furthermore, the invention relates to a manufacturing method for a rotor (1) for an electric machine.

Description

This invention relates to a rotor for an electric machine having a rotor core and magnets. The invention also relates to an electrical machine. Further, this invention relates to a manufacturing method of a rotor for an electric machine.

In the rotor laminated core of the rotor a plurality of elongated magnetic receiving slots for receiving a respective magnet in the radial direction are arranged, wherein the outer ends of the magnet receiving slots are open. An air gap at the end of the magnet receiving slots is useful to avoid creating a magnetic short circuit. A strong magnetic short circuit would make it largely impossible to use the magnets to convert electrical to mechanical energy and vice versa.

Preferably, such a rotor is used in an actuator, for example in a means of transport. In particular, such a rotor can be used for demands on a high compactness, vibration robustness and at the same time the demand for low production costs.

Off in the prior art is the patent application WO2015048955 known, according to which a rotor lamination stack is provided on the inner circumference with a toothing, which is pressed onto a shaft with complementary outer toothing.

In brushless DC motors with a stator surrounding a rotor, it is common to mechanically fix rotor magnets in a rotor lamination stack, e.g. by gluing or extrusion coating with plastic.

A rotor having surface magnets on the outer surface of the rotor having an elongate extent along the outer circumference of the rotor generally has a burst protection sleeve surrounding the surface magnets to hold the rotor together. In typical applications, such rotors are rated for 1 to 1.5 Nm of torque and a speed of 4000 to 6000 revolutions per minute.

In a positioning of magnets called a spoke arrangement, magnets with an elongate extent in the radial direction are arranged in the rotor.

The spokes arrangement of the magnets has the advantage over the arrangement with surface magnets that the magnets are better protected against demagnetization when driven in a mode with field weakening and the like. According to the prior art, the magnets are glued in most applications in the rotor core. In this case, the bonding process is complicated and sensitive with respect to requirements on the adhesive surfaces, cleanliness, coatings on the magnets, etc. It is also known to overmold the rotor laminated core with the magnets.

These solutions have in common that they are time-consuming and therefore expensive to manufacture, since adhesive must cure or a rotor core with magnets must be inserted into a tool and molded around.

The object of the invention is therefore to provide a rotor for an electric motor, which is inexpensive to produce. In addition, the rotor should make good use of the magnetic flux of the magnets.

This object is achieved by the features of the independent claims. Further advantageous developments are the subject of the dependent claims.

The invention relates to a rotor for an electric machine having between two magnet receiving slots in the vicinity of the radially inner end of the magnet receiving slots extending in the axial direction through the rotor core packet magnetic flux steering hole.

The magnetic flux steering hole is used, inter alia. for increasing the magnetic resistance in a short-circuit path of magnetic flux from an exit surface of a magnet of magnetic flux from the magnet to an entrance surface of the same magnet for magnetic flux. The arrangement near the radially inner end of the magnet receiving slots causes magnetic flux to flow less toward the interior of the rotor core. As a result, more magnetic flux flows to pole shoes adjacent to the magnet receiving slots where it can be used to convert electrical energy into mechanical energy.

Preferably, a constriction is arranged between the magnetic flux guide hole and a Magnetflusslenkausnehmung at the radially inner end of a magnet receiving slot, which increases the magnetic resistance of a magnetic short-circuit path of a magnet. Preferably, the cross-section of the bottleneck is one-fifteenth to one-thirty-fifth, preferably about one-twenty-fifth, of a magnetic flux exit surface from a magnet. By such a ratio it is achieved that the bottleneck is magnetically saturated in many operating states and thus generates a high magnetic resistance in the short-circuit path. The ratio of about one twenty-fifth is magnetic and also mechanical with respect to Strength of the bottleneck optimized. This mechanical optimization relates to forces to be transmitted by a pole shoe of a yoke section in which the magnetic flux guide hole is located.

Preferably, a rivet for holding the rotor laminated core and / or for fixing a fixing device to the rotor laminated core passes through a magnetic flux guide hole in the rotor laminated core. In this way, another benefit can be achieved by the magnetic flux steering hole. The rivets are preferably designed non-magnetic.

Preferably, the rotor has a shaft receiving opening, which has on its inner circumference connecting recesses for receiving teeth of a rotor shaft, wherein the connecting recesses are designed at its radially outer end with a rounding. This embodiment of a connecting recess, in particular in cooperation with a connecting tooth of a rotor shaft which does not extend as far as the rounding, causes the shaft receiving opening to yield. This is advantageous to use a press fit between the rotor shaft and the shaft receiving opening.

Preferably, a distance between a fillet at the end of a connection recess and a magnetic flux directing recess is about one tenth to one thirtieth, preferably about one twentieth of the outer diameter of all radially outer tips of the fillet fillet fillets. To adjust the compliance of the shaft receiving aperture, the magnetic flux directing recess may contribute to the inner end of a magnet receiving slot. A particularly good optimization, also with regard to the magnetic properties with respect to a magnetic short-circuit path, can be achieved with the o.g. Ratio of about one twentieth can be achieved.

In particular, the rotor has a fixing device for axially fixing at least one magnet in a magnet receiving slot. The fixing device causes the magnet can not move axially from the magnet receiving slots. In each case a fixing device is preferably arranged at both axial ends of the rotor laminated core.

The fixing device causes in particular an axial bias of the magnets. When the magnets are biased, they can not move relative to the rotor core, which significantly reduces wear and, if any, abrasion during vibration.

The fixing device may be configured as a cap for an axial end of the rotor or as a part thereof. The cap may for example be made of plastic, in particular of fiber-reinforced plastic, more preferably of glass fiber reinforced plastic.

The axial fixing device preferably has a contact pressure area, which is configured to be elastic in the axial direction of the rotor and which bears against a magnet, the magnet elastically deflecting the contact pressure area so that the magnet is prestressed by the contact area in the axial direction of the rotor. The pressing area may be, for example, a softening point in a cap. Such a softening point is more yielding in the axial direction of the rotor than its surroundings. The contact area may be separated from its surroundings by at least one elastication slot. This deprives the contact area, the mechanical connection to its immediate environment, so that the contact area in the axial direction is more yielding than this. In particular, the contact pressure area is surrounded on at least two sides by elasticizing slots.

The fixing device may have a projection and / or a projection, which may engage in alignment with the fixing device in a magnetic receiving slot and / or a Magnetflusslenkausnehmung. The projection limits the path of the magnet radially inwardly and the projection limits the path of the magnet radially outward. A magnet may be included in the radial direction from two sides of the fixing device. By suitable design of the projection and the projection of the magnet can be radially biased. The protrusions can fulfill a primary burst protection function for the magnets.

By engaging in a magnetic receiving slot or in a Magnetflusslenkausnehmung the fixing device may be aligned with the rotor core. An attachment can be achieved by riveting through the Magnetflusslenklöcher.

At least one magnet receiving slot has a positive retaining means for retaining a magnet in the magnet receiving slot radially outward. In this way it can be achieved that the magnets are not thrown from their magnetic receiving slots by centrifugal forces. The retaining device can fulfill a secondary burst protection function.

Preferably, the retainer is formed as a retaining projection at the outer end of the magnet receiving slot. In this way, the retention projection can be inexpensive getting produced. The retaining projection is formed on at least one side at the radially outer end of a magnet receiving slot, but preferably on both sides.

The projection of the retainer inwardly is preferably between about 10% and 30% of the width of the magnet receiving slot at the location of the retainer. Too large a protrusion creates a magnetic short circuit, while too small a supernatant can generate too high a surface pressure on the retained magnet. In addition, the retainer can perform magnetic functions on a pole piece.

Preferably, the rotor is formed in the vicinity of the retainer in the circumferential direction without recesses, which allow a magnet receiving slot can expand. Then, the retainer can not escape in the circumferential direction and release the magnet.

In a further aspect of the invention, an electric machine is proposed, which comprises a rotor according to one of the embodiments described above.

In still another aspect of the invention, a method of manufacturing a rotor of an electric motor is proposed. In a first step, a rotor laminated core is produced, which has elongated magnetic receiving slots, which are aligned in the radial direction of the rotor core, wherein the rotor has a positive radial magnetic holding device on each magnet receiving slot. The positive radial magnetic retention means causes a magnet in the magnetic retention slot to be retained radially and from the center of the rotor in the magnetic retention slot. In a second step, magnets are introduced into the magnet receiving slots. In a third step, the magnets are fixed in the magnet receiving slots in the axial direction of the rotor by means of a fixing device as described above and / or with reference to the figures.

Preferably, in the manufacturing method for axially fixing the magnets, at least one fixing device, which in particular has a resilient contact pressure area for applying an axial prestress to the magnets, is placed on an axial end of the rotor laminated core.

Preferably, the fixing device is preferably firmly connected by rivets with the rotor core.

The rivets are preferably riveted through a magnetic flux guide hole for holding together the rotor lamination stack and preferably also the fixing devices.

In other words, the invention can be described as follows. In a spokes arrangement of the magnets in a rotor for a brushless DC motor, the design of the rotor can be carried out so that at the same time the requirements of optimal design of the magnetic circuit and the fulfillment of the mechanical function of the rotor (torque transmitted, robustness against vibration, burst protection function provided , easy installation on a motor shaft) together with the requirement of a cost-optimized assembly process. When the magnets are inserted into the magnet receiving slots of the rotor laminations, the magnets can axially and radially bias by two plastic caps disposed on both sides at the axial ends of the rotor, for example by ribs, noses or other protruding portions.

By Magnetflusslenklöcher in the rotor laminations as much magnetic flux is to be brought as possible in the direction of the air gap of the electric machine on the outer circumference of the rotor. The Magnetflusslenklöcher shown in the figures are optimized by FE calculation in terms of shape and magnetic flux. At the same time these Magnetflusslenklöcher can be used for the passage of rivets for axially holding the rotor laminated core, the magnets and the plastic mounting washers as fixing.

The rotor laminated core preferably comprises compressed and usually held by punched nubs punched electrical sheets with spoke-shaped magnet receiving slots. The magnets are usually sintered permanent magnets (preferably rare earth materials) in the form of a cuboid. The fixing device designed as a cap can be made of plastic, in particular of a glass fiber reinforced plastic, in particular both caps. The rivets may serve to axially restrain the rotor core, the magnets and the plastic mounting washers. As rivets hollow rivets can be used to achieve a low mounting force in the axial direction during riveting. However, other common rivets can be used.

• - Ermöglichen eines minimalen Streuflusses von dem Magnetfeld im Rotor und
• - lokale Steifigkeitsreduzierung, um einen segmentierten Pressverband mit einer Welle zu realisieren.

The punching plates of the rotor have radially extending magnet receiving slots. By a slight projection inwards in the outer area of the magnet receiving slots, a secondary burst protection function is shown. The magnetic flux holes in the rotor plates for flux steering between the magnets have the following function: as much magnetic flux as possible should be brought to the outside in the air gap of the electric machine on the outer circumference of the rotor. These Magnetflusslenklöcher are shown in the figures and optimized by means of finite element calculation in terms of shape and magnetic flux. At the same time these Magnetflusslenklöcher can be used for the implementation of the rivets for axial attachment in the assembly of rotor core, magnets and plastic mounting washers. The structural weaknesses near the inner diameter through the Magnetflusslenklöcher, Magnetflusslenkausnehmungen and Verbindungsausnehmungen on the inner circumference of the rotor fulfill 2 functions:

• - Allowing a minimum leakage flux from the magnetic field in the rotor and
• - Local stiffness reduction to realize a segmented interference fit with a shaft.

The plastic caps can fix and fix the permanent magnets in the rotor core.

In the axial direction, the magnets of the rotor can be fixed on both sides by the two plastic caps are fixed by rivets on the circumference of the rotor. The number and arrangement of the rivets are preferably selected so as to cause a minimum imbalance of the rotor. At contact points between plastic caps and magnets each thickenings may be provided, which are provided in a non-deformed state with a projection over contact surfaces of the magnets. These contact areas can be deformed during riveting. The stiffness of the plastic cap is reduced in the immediate vicinity of these increases. This results in a deformation of the Anpressbereiche and easier bilateral axial biasing force on the magnets.

• 1 eine perspektivische Explosionsdarstellung eines erfindungsgemäßen Rotors;
• 2 eine perspektivische Ansicht eines Rotorblechpakets des Rotors:
• 3 eine perspektivische Ansicht auf eine dem Rotor abgewandte Seite einer Kappe des Rotors,
• 4 eine perspektivische Ansicht auf eine dem Rotor zugewandte Seite einer Kappe des Rotors,
• 5 eine perspektivische Ansicht des Rotorblechpakets mit beidseitig aufgesetzten Kappen in vernietetem Zustand;
• 6 eine Ansicht der Stirnseite des Rotorblechpakets mit aufgesetzter Kappen in vernietetem Zustand:
• 7 einen Schnitt parallel zu einer Stirnfläche des Rotors durch den Rotor in vernietetem Zustand; und
• 8 einen Schnitt des Rotors in vernietetem Zustand längs und durch die Mitte des Rotors.

The invention will be explained in more detail with reference to an embodiment in conjunction with accompanying drawings. Here are shown schematically:

• 1 an exploded perspective view of a rotor according to the invention;
• 2 a perspective view of a rotor core of the rotor:
• 3 a perspective view of a rotor remote from the side of a cap of the rotor,
• 4 a perspective view of a rotor-facing side of a cap of the rotor,
• 5 a perspective view of the rotor laminated core with both sides patch caps in riveted state;
• 6 a view of the end face of the rotor laminated core with attached caps in riveted state:
• 7 a section parallel to an end face of the rotor by the rotor in riveted state; and
• 8th a section of the rotor riveted state along and through the center of the rotor.

1 shows an exploded view of a rotor 1 according to the invention for an electric machine. The rotor 1 includes a rotor core 2 which has a continuous shaft receiving opening 21 and exactly ten magnet slots 23 having. Next has the rotor core 2 ten magnetic flux holes 22 on which the rotor lamination package 2 completely penetrate.

1 also shows ten parallelepiped magnets 3 , which in the magnet receiving slots 23 fit. The magnets 3 have the same length as the rotor package 2 , The magnets 3 are each from an exit surface 31 in tangential direction to the opposite entrance surface 32 Magnetized in the tangential direction, so that the north or south pole at the entrance surface 31 or the exit surface 32 are located. The magnetization direction alternates between each magnet 3 and its neighboring magnet 3 ,

On both faces of the rotor core 2 are fixators 4 Shown as caps for attaching the magnets 3 in the rotor core 2 are formed.

Far left in the 1 are five rivets 5 shown as a slotted hollow rivet with a slot 51 designed and riveted head 52 are shown. These are for fixing the fixing device 4 on the rotor core 2 and holding the rotor core together 2 intended.

2 shows in a perspective view, the rotor core 2 , Center has the rotor core 2 a shaft receiving opening 21 on. On the inner circumference of the shaft receiving opening 21 are alternately ten Verbindungsausnehmungen 211 and connecting teeth arranged, each in the axial direction of the rotor lamination stack 2 through the entire rotor core 2 run.

The ten magnet receiving slots 23 near the circumference of the rotor core 2 two restraint devices each 231 on which of the side walls of the magnet receiving slots 23 respectively towards the interior of the Magnet receiving slots 23 protrude. The retention device 231 each is about 20% of the inner width of the magnet receiving slots 23 in front. They serve to hold the magnets 3 and form in addition to the fixing projections described below 41 a secondary burst protection.

At the inboard ends of the magnet receiving slots 23 is each a magnetic flux steering recess 232 arranged. These magnetic flux deflecting recesses 232 serve to the magnetic flux of the magnets 3 short as short as possible. The magnetic flux from a magnet 3 emerges from an exit surface 32 in the circumferential direction of the magnet 3 and enters a yoke section 26 one that lies between two adjacent magnets. In principle, the magnetic flux from a yoke section 26 on one side of the magnet 3 in the adjacent yoke section 26 on the other side of the magnet 3 flow and thereby cause a magnetic short circuit. However, this is complicated by the fact that the magnetic flux thereby a first bottleneck 27 between the magnetic flux steering hole 22 and a jetty 24 must happen. If the magnetic flux is the bridge 24 has reached, he must again another first bottleneck 27 between the same magnetic flux steering recess 232 and the magnetic flux steering hole 22 of the adjacent yoke section 26 happen to the entrance area 31 same magnet 3 to reach. The first bottlenecks 27 Due to their small cross-section even at low magnetic flux into saturation, so that due to the high magnetic resistance, the short-circuit effect of the path between the exit surface 32 and the entrance area 31 a magnet 3 only small. The bulk of the magnetic flux of a magnet 3 thus comes out of the pole shoes 29 each one of the magnet 3 adjacent yoke sections 26 out or there, so that this vast majority of the magnetic flux is available for the electric machine.

When the magnetic flux along a short-circuit path is the bottleneck 27 has happened, he has a second bottleneck 28 happen between a connection recess 211 and a magnetic flux steering recess 232 is arranged. Due to the symmetrical structure of the rotor core 22 around a center of the magnet receiving slot 23 there must be another second bottleneck around 28 in the path from the exit surface 32 to the entrance area 31 of the magnet 3 be passed by the magnetic flux. These second bottlenecks 28 further increase the magnetic resistance of the exit surface 32 to the entrance area 31 ,

The cross section of the first bottleneck 27 At its narrowest point is preferably about half of the cross section of the web 24 at its narrowest point. The cross section of the second bottleneck 28 at its narrowest point is preferably about as large as the cross section of the web 24 at its narrowest point.

The magnetic flux holes 22 are preferably egg-shaped, with a Ausspitzung 221 at the top of the egg shape is directed radially outward. The magnetic flux holes 22 are preferably circumferentially centered between two magnet receiving slots 23 arranged. The radially inner end of the magnetic flux holes 22 is located near the jetty 24 , The jetty 24 is located at the radially outer end of the Magnetflusslenkausnehmungen 232 ,

The geometry of the rotor core 2 is also designed to make a good connection between the shaft receiving opening 21 and to ensure a, to be introduced in the longitudinal direction toothed rotor shaft. This should be a certain radial compliance of the shaft receiving opening 21 available. The shaft receiving opening 21 is provided for a press fit with the shaft and therefore expands elastically in the assembled state. The radially outer ends of the connection recesses 211 are each with a rounding 2121 executed. At these fillets 2121 are the second bottlenecks 28 , Their cross section therefore also contributes to the resilience of the shaft receiving opening 21 at. Preferably, the distance between a rounding 2121 at the end of a connection recess 211 and a magnetic flux steering recess 232 about one twentieth of the outer diameter of the radially outer peaks of the fillets 2121 the connection recesses 211 , On the rotor shaft arranged in the longitudinal direction of the teeth are preferably not up to the radial outer end of the connecting recess 211 before, but ends further inside.

3 shows a fixing device 4 in a perspective view. The fixing device 4 is as a cap for mounting on an axial end of the rotor core 2 designed. The side facing the viewer is the side which in the mounted state of the rotor laminated core 92 is directed away.

The fixing device 4 is designed ring-shaped. It points for every second magnetic flux steering hole 22 a rivet hole 42 on. Every rivet hole 42 has a chamfer 421 , The chamfer 421 is for receiving a rivet head 52 a rivet provided. The fixing device 4 is preferably made of glass fiber reinforced plastic.

The fixing device 4 points for every magnet 3 a contact area 43 on. The contact area 43 is from its environment through two elastication slots 431 one of which is surrounded on two opposite sides, from the rest of the fixing 4 partially separated. This results in greater compliance of the contact area 43 compared to the rest of the fixator 4 caused.

4 shows the fixing device 4 in a perspective view. The side facing the viewer is the side which, when assembled, is the rotor core 92 is facing.

The fixing device 4 has at its periphery in the axial direction for each magnet receiving slot 23 a fixing projection 41 on. The fixing projection 41 is designed slim. Show at his free end a pressure nose 411 on the inside.

The fixing device 4 points near its inner circumference 45 one projection for each magnet receiving slot 44 on. The cantilever 44 is intended to be in a magnetic flux steering recess 232 of the rotor core 2 to be plugged. The cantilever 44 has two wings in the circumferential direction 443 on, which for abutment with the Magnetflusslenkausnehmung 232 are provided. Next has the projection 44 a jetty 442 on which to attach to a magnet 3 is provided. The distance between the presser nose 411 and the Andrucksteg is preferably less than the length of the magnet, which is in the assembled state therebetween. In this way, the magnet is biased in the radial direction held in position. The Fixiervorsprünge 41 serve as primary burst protection.

The contact areas 43 carry on their the rotor sheet package 2 each side facing an increase, which for abutment with the magnets 3 is provided. The magnets are between two such contact areas 43 arranged. The geometry of the rotor 1 is designed such that the Anpressbereiche 43 in the mounted state axially of the rotor core 2 be deflected away elastically. This is how the magnets are made 3 inside the rotor 1 biased in the axial direction.

5 shows the rotor 1 in assembled condition. The caps designed as fixing 4 are on both ends of the rotor core 2 placed. The Fixiervorsprünge 41 engage in the radial ends of the magnet receiving slots 22 one of which is in 5 only the restraints 211 you can see. The Fixiervorsprünge 41 are each between the associated retention devices 211 arranged.

The fixators 4 are on the rotor laminated core with five rivets 5 attached. The rivets 5 pass through the magnetic flux holes 22 , in the 5 not to be seen. At the rivets 5 are rivet heads on both sides 52 formed. At the rivets 5 are hollow rivets. The rivets are with a slot 51 executed in the longitudinal direction.

6 shows a view of an end face of the mounted rotor 1 , Here it can be seen that only a part of the Verbindungsausnehmungen 211 inside the inner circumference 45 the fixing device 4 is arranged.

7 shows a section parallel to an end face of the rotor core 2 through the rotor core 2 in the assembled state.

It is shown as a magnet 3 between a fixing projection 41 and a pressure bar 442 the fixing device 4 is trapped. Due to the flexibility of the Fixiervorsprungs 41 is the magnet 3 biased in the radial direction.

The cantilever 44 the fixing device 4 is within the magnetic flux steering recess 232 arranged. The cantilever 44 lies with her wings 443 on the inner surface of the magnetic flux guide recess 232 at. This will make the magnets 3 in the radial direction on the rotor laminated core 2 fixed. At the same time this jamming of the projections 44 the fixing device 4 on the rotor core 2 provisionally fasten. To facilitate insertion, the cantilever can 44 a Einfädelfase 441 have, in 4 is shown.

In 27 you can see how five rivets 5 through every second of the magnetic flux holes 22 Run.

8th shows a longitudinal section through a moon fourth rotor 1 , It can be clearly seen that the rotor laminated core has a multiplicity of stacked rotor laminations 25 having. It can also be seen that a rivet 5 a head 52 at each of its ends. Each of the heads 52 lies on an outer end face of the fixing device 4 on.

LIST OF REFERENCE NUMBERS

1

rotor

2

Laminated core

21

Shaft receiving hole

211

connecting recess

2121

rounding

212

connecting tooth

22

Magnetic flux steering hole

221

thinning

23

Magnet receiving slot

231

Restraint

232

Magnetflusslenkausnehmung

24

web

25

rotor sheet

26

yoke

3

magnet

4

Axial fixation device

41

fixing projection

411

Andrucknase

42

rivet hole

421

chamfer

43

pressing region

431

Elastifizierungsschlitz

44

projection

441

Einfädelfase

442

pressure bar

443

wing

5

rivet

51

Nietschlitz

52

rivet head

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• WO 2015048955 [0004]

Claims (10)

Rotor (1) for an electrical machine with a rotor laminated core (2) and magnets (3), wherein in the rotor laminated core (2) a plurality of elongated magnet receiving slots (23) for receiving a respective magnet (3) are arranged in the radial direction, wherein the outer Ends of the magnet receiving slots (23) are open, characterized in that between two magnet receiving slots (23) in the vicinity of the radially inner end of the magnet receiving slots (23) in the axial direction through the rotor core (2) extending magnetic flux steering hole (22) is arranged. Rotor (1) to Claim 1 , characterized in that between the Magnetflußlenkloch (42) and a Magnetflusslenkausnehmung (232) at the radially inner end of a magnet receiving slot (23) has a constriction (27) is arranged, which increases the magnetic resistance of a magnetic shorting path of a magnet (3), preferably the cross-section of the constriction (27) is one-fifteenth to one-thirty-fifth, preferably about one-twenty-fifth of an exit surface (32) of magnetic flux from a magnet (3). Rotor (1) according to one of the preceding claims, characterized in that a rivet (5) for holding the rotor laminated core (2) and / or for fixing a fixing device (4) on the rotor laminated core (2) by a magnetic flux guide hole (23) in the Rotor laminated core (2) runs. Rotor (1) according to one of the preceding claims, characterized in that the rotor (1) has a shaft receiving opening (21), which on its inner circumference connecting recesses (211) for receiving teeth of a rotor shaft, wherein the connecting recesses (211) at its a distance between a rounding (2121) at the end of a connecting recess (211) and a Magnetflusslenkausnehmung (232) about one tenth to one thirtieth, preferably about one twentieth, the outer diameter of radially outer peaks of the fillets (2121) of the connecting recesses (211) is. Rotor (1) according to one of the preceding claims, characterized in that the rotor (1) has a fixing device (4) for axially fixing at least one magnet (3) in a magnet receiving slot (23), wherein by means of the fixing device (4) in particular a axial bias of the magnets (3) in the mounted state of the rotor (1) is effected, and / or wherein the fixing device (4) is preferably designed as a cap for an axial end of the rotor (1). Rotor (1) to Claim 5 , characterized in that the axial fixing device (4) has a contact pressure region (43) which is elastically deflectable in the axial direction of the rotor (1) and which rests against a magnet (3), the magnet (3) covering the contact pressure region (43 ) deflects elastically, such that the magnet (3) of the contact pressure region (43) is biased in the axial direction of the rotor (1), wherein in particular the contact pressure region (43) is separated from its surroundings by at least one Elastifizierungsschlitz (411). Rotor (1) to Claim 6 , characterized in that the fixing device (4) has a projection (44) and / or a projection (41) which - for the alignment of the fixing device (4) With respect to the rotor core (2) and / or - Preloading the magnets (3) engages in the radial direction in - a magnetic receiving slot (23) and / or - a Magnetflusslenkausnehmung (232). Manufacturing method for a rotor (1) of an electric machine, in which in a first step, a rotor lamination stack (2) is produced, which has a plurality of elongate magnet receiving slots (23) which are aligned in the radial direction of the rotor lamination stack (2), - In a subsequent second step, magnets (3) are introduced into the magnet receiving slots (23) and - In a subsequent third step, the magnets (3) in the magnet receiving slots (23) by means of a fixing device (4) in the axial direction of the rotor (1) are fixed. Production method according to Claim 8 in which at least one fixing device (4), which in particular has a resilient contact pressure area (43) for applying an axial prestress to the magnets (3), is placed on an axial end of the rotor lamination stack (2) for axially fixing the magnets (3) , wherein the fixing device (4) is preferably firmly connected by rivets (5) with the rotor laminated core (2). Production method according to Claim 8 or 9 in which rivets (5) are riveted to hold the rotor lamination stack (2) together through a magnetic flux guide hole (22), preferably the Rivets (5) consist at least largely of non-magnetic material.

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