Rotor for an electric machine and electric machine having the rotor

Abstract

The invention relates to a rotor (3) for an electric machine (1), having: a plurality of rotor poles (4) distributed in a circumferential direction; at least one permanent magnet (8) per rotor pole (4); at least one laminated core (5), wherein the laminated core (5) has a plurality of main laminations (12) stacked in an axial direction (103) with respect to a main axis of rotation (100), wherein the main laminations (12) per rotor pole (4) each have at least one receiving opening (17a, 17b), each of which has a magnet receiving portion (8) for forming a magnet receptacle (7a, 7b) for the permanent magnet (8) and at least one filling channel portion (19a, 19b) laterally adjacent to said magnet receiving portion for forming a filling channel (9a, 9b); a filling compound (10) which is arranged at least in some portions in the respective filling channel (9a, 9b) in order to fix the permanent magnets (8) in the respective magnet receptacle (7a, 7b), wherein the laminated core (5) has at least one delimiting intermediate lamination (13) which is arranged within the laminated core (5) at a distance (105) from an axial end face in the axial direction (103), wherein the filling compound (10) is delimited in the axial direction (103) by the delimiting intermediate lamination (13).

Description

[0001] Rotor for an electric machine as well as an electric machine with the rotor

[0002] The invention relates to a rotor for an electric machine having the features of the preamble of claim 1. The invention further relates to an electric machine with the rotor.

[0003] Electrical machines are known that have a rotor and a stator. The rotor is typically designed as a laminated core, formed by several stacked laminated sheets. The rotor also includes several permanent magnets, which are held in recesses in the laminated core to form rotor poles. For this purpose, the individual laminated sheets have corresponding recesses, arranged one behind the other such that the recesses are aligned with each other, thus forming the recesses. It is known to fill these recesses with a potting compound to fix the magnets within them.

[0004] For example, US patent 2023,145,591 A1 discloses a rotor comprising a rotor core with magnetic poles arranged circumferentially around a central axis, each magnetic pole comprising magnetic pockets, each of which has an opening end that opens to an outer circumference of the rotor core. The rotor further comprises a first core section between adjacent magnetic pockets, a second core section between the magnetic pockets and the central axis, and a bridge connecting the first core section and the second core section. The rotor also includes permanent magnets arranged in the respective magnetic pockets and a non-magnetic filler material that is filled into a cavity between the permanent magnet and the opening end of the magnetic pocket and is connected to the permanent magnet and an inner wall of the magnetic pocket.

[0005] It is an object of the present invention to provide a rotor for an electric machine characterized by a reliable fixation of the permanent magnets in the laminated core. This object is achieved by a rotor with the features of claim 1 and an electric machine with the features of claim 15. Preferred or advantageous embodiments of the invention are described in the dependent claims, the following description, and the accompanying figures.

[0006] The invention relates to a rotor designed and / or suitable for an electric machine. In particular, the electric machine is designed as an internal rotor motor with an internal rotor and an external stator. Alternatively, the electric machine can also be designed as an external rotor motor with an internal stator and an external rotor. Preferably, the rotor defines a main axis of rotation with its axis of rotation.

[0007] The rotor has several rotor poles distributed in a circumferential direction. The rotor poles preferably each have a pole center axis extending radially with respect to the main axis of rotation, and the rotor poles are symmetrical with respect to their respective pole center axis. In particular, the rotor lamination stack has more than four, preferably more than six, and specifically more than eight rotor poles, which are uniformly distributed in the circumferential direction.

[0008] The rotor has at least one pole-generating permanent magnet per rotor pole. In other words, a rotor pole is defined by at least one permanent magnet. In particular, the permanent magnets are designed as cuboid bar magnets.

[0009] The rotor has at least one lamination stack, which comprises several main laminations stacked in an axial direction with respect to the main axis of rotation. Preferably, the main laminations are stacked coaxially with respect to the main axis of rotation and / or congruently on top of each other in the axial direction. The individual main laminations are preferably made of sheet metal laminations manufactured from electrical steel. The sheet metal laminations can, for example, be stamped from a rolled steel coil (strip steel rolls). Preferably, the main laminations are electromagnetically optimized and therefore particularly preferably occur most frequently within the lamination stack. In principle, the lamination stack forms a rotor lamination stack of the rotor.Alternatively, the lamination stack forms a partial lamination stack of the rotor lamination stack, wherein at least two of the partial lamination stacks are stacked on top of each other in the axial direction to form the rotor lamination stack and / or are twisted relative to each other by a skew angle to form a skew in the circumferential direction.

[0010] The main lamellae each have at least or exactly one receiving opening per rotor pole, each of which has a magnet receiving section to form a magnet receptacle for the permanent magnet and at least or exactly one laterally adjacent filling channel section to form a filling channel. In other words, the magnet receiving section and the filling channel section for each rotor pole are jointly formed by the receiving opening in the main lamella. Put simply, the magnet receiving section and the filling channel section are directly connected to each other. For example, the filling channel sections each form a flux barrier. Preferably, the at least one filling channel section is arranged on a narrow side of the magnet receiving section. In particular, each rotor pole has several magnet receptacles arranged in a formation, with at least one permanent magnet being arranged in each of the magnet receptacles.For this purpose, the main lamellae have at least one receiving opening with a magnet receiving section and at least one filling channel section for each magnet receptacle.

[0011] The rotor has a filling compound that is arranged at least partially in the filling channel to fix the permanent magnets in their respective magnet holders. In particular, the filling compound serves to fix the permanent magnet in its respective magnet holder without play, preferably in all spatial directions. For this purpose, the filling compound is preferably filled into the filling channels axially and / or at an axial end face, preferably by injection. Preferably, each magnet holder is assigned at least one or exactly one filling channel, which is filled at least partially with the filling compound to fix the at least one permanent magnet in its respective magnet holder. The filling compound can be an adhesive or a plastic.The invention proposes that the lamella stack comprises at least one or exactly one limiting intermediate lamella, which is arranged within the lamella stack at a distance in the axial direction from an axial end face, wherein the filling material is limited in the axial direction by the limiting intermediate lamella. In particular, the limiting intermediate lamella serves to prevent the filling material from flowing further beyond a defined axial length of the lamella stack. A limiting intermediate lamella is thus understood to be a sheet metal lamella which is arranged axially between two adjacent sheet metal lamellae, preferably two main lamellae, within the sheet metal stack in order to limit the filling channel in the axial direction from the axial end face.Put simply, the limiting intermediate lamella ensures that part of the filling channel up to the limiting intermediate lamella is filled with the filling material, and part of the filling channel after the limiting intermediate lamella is not filled with the filling material.

[0012] Optionally, the lamella stack has at least one additional intermediate limiting lamella. This additional intermediate limiting lamella can be positioned directly downstream of the first to reinforce the first. Alternatively or additionally, the additional intermediate limiting lamella can be positioned axially spaced from another axial end face within the lamella stack, with the filler material being limited in the opposite axial direction by the additional intermediate limiting lamella. This allows the permanent magnets to be fixed on both sides within their respective magnet receptacles by an axially limited filler material.

[0013] The invention is based on the understanding that the laminated core can have any axial length. To fix the permanent magnets in the magnet holders, for example by injection molding, the entire laminated core must be heated. This prevents the molten, hot plastic from coming into contact with a cold laminated core and cold permanent magnets, thus preventing the melt from solidifying too quickly. If the melt solidifies too early within the filling channel, it will not be completely filled with the filler material, and the permanent magnets will not be adequately fixed. Heating the entire laminated core can take from a few seconds to several minutes and is energy-intensive, thus increasing costs. The process of overmolding the permanent magnets in the magnet holders is limited by the melt temperature, maximum filling pressure, and the minimum and maximum volume that can be filled.In general, the filling channels are very small and the filling pressure can only be increased up to a certain point. Therefore, the lamination stack cannot be made arbitrarily long, as the molten filling material freezes at a depth of just a few centimeters despite high filling pressure, and the melt does not completely fill the cavity. For this reason, PSM rotor lamination stacks are typically manufactured in partial lamination stacks.

[0014] The advantage of this invention lies in the fact that the axial limitation allows a portion of the filling channels to be reliably and completely filled with the filling material, thus preventing defects such as air inclusions and incomplete filling of the channels. This enables the permanent magnets to be fixed easily and reliably in their respective magnet holders. Furthermore, the axial limitation reduces the required amount of filling material compared to completely filling the channels. Another advantage is that the limited filling of the channels eliminates the need for complete heating of the lamination stack, thereby reducing heating time. Additionally, a rotor of any axial length can be implemented, while simultaneously minimizing the number of rotor lamination stacks and permanent magnets.This reduces the number of individual parts that need to be assembled, as fewer magnets need to be fixed in a single laminate pack or a smaller number of partial lamination stacks. The resulting rotor design thus reduces assembly effort and can therefore be manufactured more cost-effectively.

[0015] In a specific embodiment, the at least one intermediate limiting lamella per rotor pole has a reduced receiving opening, which includes a magnet receiving section to form the magnet receptacle. At least one material section adjacent to the magnet receiving section is arranged to axially limit the filling material, overlapping, particularly in the axial direction, the filling channel section of the main lamellae. In other words, the material section projects into the filling channel in such a way that it is interrupted in the axial direction. Specifically, a reduced receiving opening is understood to be a receiving opening that has a reduced opening cross-section and / or diameter compared to the receiving opening of the main lamellae. In other words, the intermediate limiting lamella has the material section instead of the filling channel section.In particular, the magnet receiving sections of the main lamellae and the intermediate limiting lamella are identical in design and / or arranged congruently with each other. A limiting intermediate lamella is therefore proposed which is essentially identical in design to the main lamellae, except that a material section is provided instead of the filling channel sections. For example, the limiting intermediate lamella can thus be manufactured particularly easily, especially by stamping, with only a minor modification to the receiving openings.

[0016] In a further development, it is provided that the material section of the limiting intermediate lamella extends to the permanent magnet, forming a tolerance gap. This tolerance gap is dimensioned such that it forms a gap seal for the filling material with the permanent magnet. Specifically, a gap seal is understood to be a non-contact seal between the material section and the permanent magnet, which seals the filling channel in the axial direction. In other words, the material section completely covers the filling channel in the axial direction and remains in contact with the permanent magnet. The tolerance gap serves, on the one hand, to compensate for tolerances between the magnet holder and the permanent magnet during assembly, and on the other hand, it forms a sealing gap for the gap seal. This sealing gap is preferably so small that the filling material cannot flow through it.The tolerance gap ensures easier installation of the permanent magnets in the magnet receptacles, preventing them from being hindered by the material sections of the limiting intermediate lamella during insertion. Furthermore, the tolerance gap ensures a seal for the filling channel. In a further embodiment, at least one or exactly one receiving opening per rotor pole has an additional filling channel section opposite the filling channel section and laterally adjacent to the magnet receptacle section, forming a further filling channel for each rotor pole. This additional filling channel is filled with the filling material in the axial direction up to the limiting intermediate lamella. Specifically, the magnet receptacle section is connected to the filling channel section and the additional filling channel section.Preferably, the two filling channel sections are each arranged on a narrow side of the magnet receptacle section and / or each form a flow barrier. The two filling channels can be fluidically separated from each other. Alternatively, the filling channels or filling channel sections can also be fluidically connected, e.g., via a connecting area of ​​the magnet receptacle sections. The connecting area can, for example, be formed by an additional tolerance gap on a long side of the permanent magnets. Particularly preferably, the magnet receptacles with two filling channels are designed as buried magnet receptacles and / or closed towards the outer circumference. A particularly secure seating of the permanent magnets in the magnet receptacles is ensured by a double-sided arrangement of filling channels.

[0017] In a further development, it is provided that the filling material completely fills the filling channel and / or the subsequent filling channel within the distance up to the limiting intermediate lamella. In other words, the filling channel and the subsequent filling channel are completely filled with the filling material in the axial direction up to the limiting intermediate lamella. The invention is based on the finding that, depending on the filling method and manufacturing process, defects such as air inclusions occur more frequently from an axial package length of approximately 50 mm, since the plastic melt partially or completely freezes from this length. Preferably, the axial distance between the end face and the limiting intermediate lamella is dimensioned such that filling of the filling channels with the filling material is ensured. Preferably, the axial distance between the axial end face and the limiting intermediate lamella is therefore less than 50 mm, preferably less than 40 mm, and specifically less than 30 mm.This ensures complete filling of the filling channels. In a further specification, it is provided that the at least one intermediate limiting lamella has an additional material section opposite the material section and laterally adjacent to the magnet receiving section of the at least one reduced receiving opening for axial limitation of the filling material. This additional material section is arranged to overlap the additional filling channel section of the main lamellae, particularly in the axial direction. In other words, the additional material section projects into the additional filling channel in such a way that it is interrupted in the axial direction. Specifically, the intermediate limiting lamella has the additional material section instead of the additional filling channel section.Specifically, the further material section of the limiting intermediate lamella extends to the permanent magnet, forming an additional tolerance gap, the additional tolerance gap being dimensioned such that it forms a gap seal for the filling material together with the permanent magnet. The two material sections are particularly preferably designed to be mirror images of each other.

[0018] In a further embodiment, at least one receiving opening per rotor pole, or optionally at least one additional receiving opening per rotor pole, has a free space section opposite the filling channel section and laterally adjacent to the magnet receiving section to form a magnet-free free space for each rotor pole. The free space sections of the main lamellae are open towards the outer circumference. In other words, the main lamellae have no closed webs at the outer circumference, particularly in the area of ​​the magnet receiving sections, thereby improving the electromagnetic properties. Specifically, the free space sections face an outer circumference of the lamella stack and / or are arranged radially outwards. Alternatively or additionally, the filling channel sections face away from the outer circumference and / or are arranged radially inwards.Particularly preferred are the magnet receptacles with a free space, designed as magnet receptacles open towards the outer circumference. The invention is based on the understanding that magnetic field lines penetrate the sheet metal of the lamination stack poorly when magnetic resistance is high. The same occurs at the usually very thin webs on the rotor's outer diameter, which is why it is advantageous to remove these completely, provided the rotor strength allows it. To ensure that the full torque of the permanent magnets can be utilized and that they are not crushed during manufacturing or in the assembled rotor, the permanent magnets should always be sufficiently covered by electrical steel laminations. Thus, a rotor with improved electromagnetic properties is proposed.

[0019] In a specific embodiment, it is provided that the free space is free of filler material. The invention is based on the understanding that when a lamellar pack with open magnet receptacles on the outer diameter is filled with filler material for magnet fixation, it can happen that the filler material is not enclosed and flows out of the open spaces in an undefined manner. By leaving the spaces free, the filler material is prevented from escaping when they are open.

[0020] In a further specification, it is provided that the lamellar assembly has at least one or exactly one limiting end lamella, which is arranged axially at the axial end face of the lamellar assembly, wherein the filling material is limited in the direction of the outer circumference by the limiting end lamella. In particular, the limiting end lamella has the function of preventing the filling material from flowing further in the direction of the outer circumference. A limiting end lamella is thus understood to be a sheet metal lamella which is arranged axially at the end face, preferably adjacent to a main lamella, of the lamellar assembly in order to limit the filling material from the axial end face in the direction of the outer circumference. In simplified terms, the limiting end lamella prevents the filling material from escaping to the outside or into the free space.

[0021] In a further development, it is provided that the limiting end lamella has at least or exactly one receiving opening per rotor pole, which has a magnet receiving section to form the magnet receptacle and a filling channel section adjacent to it laterally to form the filling channel. Furthermore, a web section opposite the filling channel section and adjacent to the magnet receiving section is arranged to limit the filling material in the direction of the outer circumference, overlapping, particularly in the axial direction, with the magnet receiving section and / or the free space section of the main lamellae.

[0022] Preferably, the web section is arranged to form a gap seal with the permanent magnet. In particular, the web section is understood to be a very thin web on the outer circumference, which serves to confine the filler material towards the outer circumference so that the filler cannot escape towards the outer circumference if the magnet receptacle is opened. Preferably, the web section is electromagnetically optimized and / or very thin, thereby reducing the magnetic resistance. In particular, the magnet receptacle sections and the filler channel sections of the main lamellae and the limiting end lamella are identical in design and / or arranged congruently with each other. The web section can be provided only in the area of ​​the magnet receptacle where the tolerance compensation between the lamella stack and the permanent magnet takes place.A limiting end lamella is therefore proposed, which is essentially identical in construction to the main lamellae, except that the magnet receiving section is limited by the web section in the direction of the outer circumference. For example, the limiting end lamella can be manufactured particularly easily, especially by stamping, with only a minor modification to the receiving openings compared to the main lamellae.

[0023] In a further development, it is provided that the at least one limiting end lamella per rotor pole has a free space section adjacent to the web section to form the magnet-free free space, wherein the magnet receiving section and the free space section are separated from each other by the web section. In particular, the free space section adjacent to the web section serves to reduce the magnetic resistance of the web section. Preferably, the free space section is arranged congruently and / or overlapping, particularly in the axial direction, the free space section of the main lamellae. Preferably, the filling material can be injected into the filling channel via the limiting end lamella, wherein the filling material is injected in the region of the magnet receiving section of the limiting end lamella.In this process, the filling material can flow into the filling channel via the filling channel section of the limiting end lamella and is limited in the direction of the outer circumference by the web section, thus preventing it from flowing further into the free space. A lamella assembly is therefore proposed in which a portion of the flow barriers can be reliably and completely filled with plastic.

[0024] In a further embodiment, the lamella assembly is provided with at least one clamping lamella for clamping the permanent magnet in the magnet receptacle. In particular, the clamping lamella serves to pre-fix the permanent magnets, preferably until the filling channels are filled with the filling material. The clamping lamella has at least one receiving opening for each rotor pole, each of which has a magnet receptacle section for forming the magnet receptacle for the permanent magnet and at least one laterally adjacent filling channel section for forming the filling channel. Preferably, the clamping lamella has at least one clamping element for each magnet receptacle for clamping the permanent magnet in the respective magnet receptacle.During the installation of the permanent magnets, the clamping elements are elastically and / or plastically deformed in the axial direction to securely hold the permanent magnets in their respective magnet holders by forming a frictional and / or force-fit connection. For this purpose, the clamping elements project, particularly transversely to the axial direction, far enough into the magnet holder section that they are deformed when the permanent magnets are inserted, preferably at a bending edge. The number of clamping lamellae depends on the desired clamping force exerted by the clamping element on the permanent magnet. In principle, the clamping elements can be arranged on the top of a broad side and / or on the side of a narrow side of the magnet holder section. Specifically, however, the permanent magnets are intended to be subjected to a clamping force radially outwards and / or pressed against a radially outer edge of the magnet holder.

[0025] This ensures that the permanent magnets do not break due to the high centrifugal forces that occur at high rotor speeds. Furthermore, there are electromagnetic advantages to the permanent magnets being positioned precisely within their magnet receptacles. In particular, the magnet receptacle sections of the main lamellae and the clamping lamellae are identical in design and / or arranged congruently with each other. A clamping lamella is thus proposed that is essentially identical in design to the main lamellae, with the clamping lamellae additionally equipped with the clamping elements.

[0026] Alternatively or optionally, the lamella stack is provided to have at least one bending edge lamella for forming a bending edge for the clamping element. In particular, the bending edge lamella serves to define a bending edge and / or to receive the clamping element. Specifically, the bending edge establishes the position at which the clamping element is bent by inserting the permanent magnet. The bending edge lamella has at least one receiving opening per rotor pole, each of which has a magnet receiving section to form the magnet receptacle for the permanent magnet and at least one laterally adjacent filling channel section to form the filling channel. Preferably, the bending edge lamella has at least one recess per magnet receptacle to define the bending edge and / or to receive the clamping element.In particular, at least one clamping element is received, at least partially, in the recess in its deformed state. During the installation of the permanent magnets, the clamping elements are bent at the bending edge of the immediately adjacent bending edge lamella, whereby the clamping element then fits into the recess of the bending edge lamella. The number of successive bending edge lamellae depends on the sheet thickness and the length of the clamping element. The deformation of the clamping element into the recess reduces the air gap formed between the permanent magnet and the magnet receptacle, which has a positive effect on the electromagnetic properties. In particular, the magnet receptacle sections of the main lamellae and the bending edge lamella are identical in design and / or arranged congruently with each other.A bending edge lamella is thus proposed, which is essentially identical in construction to the main lamellae, with the bending edge lamellae additionally provided with the recesses. In a further development, it is provided that the intermediate limiting lamella and / or the end limiting lamella each have at least one clamping element for clamping the permanent magnet in the magnet receptacle. In particular, the at least one clamping element is formed integrally with the magnet receptacle section and / or the material section of the intermediate limiting lamella. Alternatively or optionally, the clamping element is formed integrally with the magnet receptacle section and / or the web section of the end limiting lamella. Preferably, all receiving openings of the intermediate limiting lamella or the end limiting lamella each have the at least one clamping element.In other words, the intermediate limiting lamella and / or the end limiting lamella simultaneously form a clamping lamella, as previously described. Preferably, the intermediate limiting lamella designed as a clamping lamella is arranged in the lamella stack between a main lamella and a bending edge lamella. Preferably, the end limiting lamella designed as a clamping lamella is arranged at the end of the lamella stack, particularly in one mounting direction of the permanent magnet, adjacent to a bending edge lamella. By designing the intermediate limiting lamella and / or the end limiting lamella as a clamping lamella, the number of special lamellae in the lamination stack can be reduced.

[0027] Alternatively, the intermediate limiting lamella and / or the end limiting lamella have a bending edge for a clamping element of an adjacent clamping lamella. In particular, the bending edge is defined by a recess. The recess can be formed, preferably at the location of the clamping element, on the magnet receiving section and / or the material section of the intermediate limiting lamella. Alternatively or optionally, the recess is formed, preferably at the location of the clamping element, on the magnet receiving section and / or the web section of the end limiting lamella. Preferably, all receiving openings of the intermediate limiting lamella or the end limiting lamella each have the at least one bending edge or the recess. In other words, the intermediate limiting lamella and / or the end limiting lamella simultaneously form a bending edge lamella, as previously described.Preferably, the intermediate limiting lamella, designed as a bending-edge lamella, is arranged within the lamella stack between a clamping lamella and a bending-edge lamella, or between a bending-edge lamella and a main lamella, or between two bending-edge lamellae. Preferably, the end limiting lamella, also designed as a bending-edge lamella, is arranged at the end of the lamella stack, particularly opposite to the mounting direction of the permanent magnet, adjacent to a clamping lamella or a bending-edge lamella. By designing the intermediate limiting lamella and / or the end limiting lamella as a bending-edge lamella, the number of special lamellae in the lamination stack can be reduced.

[0028] In a further specific implementation, it is provided that the pole arrangements each have a pole center that divides the pole arrangement into two pole halves, wherein at least or exactly one magnet receptacle and at least one adjacent filling channel are arranged in each pole half, which are mirror-symmetrical with respect to the pole center. Preferably, the lamella stack comprises more than two, preferably more than four, and in particular more than six of the magnet receptacles per rotor pole. For example, the lamella stack has 2n, 3n, 4n, 5n, or 6n magnet receptacles, where n corresponds to the number of rotor poles. The magnet receptacles can, for example, be arranged in a single or multiple row in a V-shaped or triangular formation. Alternatively or optionally, one or more of the magnet receptacles per rotor pole are designed to accommodate more than one, preferably two, permanent magnets arranged axially one behind the other.In particular, the magnet receptacles are designed as axially continuous magnet pockets into which the permanent magnets are axially inserted or inserted. Preferably, at least two magnet receptacles per rotor pole are designed as open magnet receptacles. Specifically, the open magnet receptacles are open towards the outer circumference or connected with a filling channel and a free space. Alternatively or optionally, at least one magnet receptacle per rotor pole is designed as a closed magnet receptacle. Specifically, the closed magnet receptacles are closed towards the outer circumference or connected on both sides with a filling channel. A further aspect of the invention relates to an electric machine with the laminated core arrangement as described above. In particular, the electric machine is designed and / or suitable for an electric axle drive and / or for driving a motor vehicle.Preferably, the electric machine is designed as an internal rotor, with the rotor arranged radially within a stator. For example, the electric machine can be designed as a traction machine, also known as a separate motor-generator (SMG). A permanent magnet synchronous machine (PSM) is particularly preferred.

[0029] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These include:

[0030] Fig. 1 shows an axial view of an electric machine with a stator and a rotor as an embodiment of the invention;

[0031] Fig. 2 shows an axial view of a rotor pole of the rotor from Fig. 1;

[0032] Fig. 3 is a perspective view of a lamella pack of the rotor from Fig. 1;

[0033] Fig. 4 is a perspective view of the rotor from Fig. 1, in which individual sheet metal lamellae are hidden;

[0034] Fig. 5 shows an axial view of a main lamella of the lamella pack from Fig. 3;

[0035] Fig. 6 shows an axial view of a boundary intermediate lamella of the lamella pack from Fig. 3;

[0036] Fig. 7 shows an axial view of a limiting end lamella of the lamella pack from Fig. 3;

[0037] Fig. 8 shows an axial view of a clamping lamella of the lamella pack from Fig. 3; Fig. 9 shows an axial view of a bending edge lamella of the lamella pack from Fig. 3;

[0038] Fig. 10 shows a perspective view of a rotor pole of the lamellar package from Fig. 3;

[0039] Fig. 11 shows a perspective view of the filling material of the rotor from Fig. 1.

[0040] Figure 1 shows an electric machine 1, in particular a permanent magnet synchronous machine, in an axial view with respect to a main axis of rotation 100. The electric machine 1 has a stator 2, shown only schematically, and a rotor 3 arranged radially inside the stator 2, which is rotatable relative to the stator 2 about the main axis of rotation 100. In simplified terms, the electric machine 1 is designed as an internal rotor.

[0041] The rotor 3 has several rotor poles 4 evenly distributed around the rotor axis of rotation 100 in the circumferential direction, each of which is bounded circumferentially by pole edges 101a, 101b extending along a so-called q-axis. Each rotor pole 4 has a pole center 102, which corresponds to a so-called d-axis. In the illustrated embodiment, the rotor 3 has exactly six rotor poles 4.

[0042] The rotor 3 has at least one lamination stack 5, which is formed by a plurality of several sheet metal laminations stacked one above the other in the axial direction with respect to the main axis of rotation 100. The lamination stack 5 has a central shaft receptacle 6 for receiving a rotor shaft (not shown) and several magnet receptacles 7a, 7b for receiving a permanent magnet 8 each.

[0043] Each of the rotor poles 4 has six magnet receptacles 7a, 7b, the magnet receptacles 7a, 7b being arranged symmetrically within the corresponding pole edges 101a, 101b and with respect to the pole center 102. At least one permanent magnet 8 is arranged in each of the magnet receptacles 7a, 7b, the permanent magnet 8 being inserted axially into the respective magnet receptacle 7a, 7b with respect to the main axis of rotation 100 and secured against loss. For example, the permanent magnets 8 are each designed as cuboid bar magnets.

[0044] The lamella assembly 5 has at least one filling channel 9a, 9b adjacent to each magnet receptacle 7a, 7b, which is directly connected to the magnet receptacle 7. The filling channels 9a, 9b are at least partially filled with a curable filler material 10 to fix the permanent magnets 8 in the respective magnet receptacle 7a, 7b without play. A plastic, for example, can be used as a cost-effective filler material 10. Depending on the type of plastic, this is melted and injected into the filling channels 9a, 9b, for example, via an injection mold.

[0045] Figure 2 shows one of the rotor poles 4, as indicated in Figure 1. For each rotor pole 4, three magnet receptacles 7a, 7b are arranged in a radially outer V-formation, and three magnet receptacles 7a, 7b are arranged in a radially inner V-formation. Both the outer and inner V-formations have two magnet receptacles 7a arranged symmetrically to the pole center 102 and open towards the outer circumference, and one magnet receptacle 7b arranged centrally to the pole center 102 and closed towards the outer circumference. In other words, a closed magnet receptacle 7b is arranged centrally between two open magnet receptacles 7a.

[0046] The open magnet receptacles 7a are each connected on one narrow side to a filling channel 9a and on the opposite narrow side to a magnet-free free space 11, which is open towards the outer circumference. The free space 11 is free of filling material 10, i.e., not filled with the filling material 10. Thus, the permanent magnets 8 arranged in the open magnet receptacles 7a are fixed on one side by the filling material 10. The closed magnet receptacles 7b, on the other hand, are each connected on both narrow sides to a filling channel 9a, 9b. Thus, the permanent magnets 8 arranged in the closed magnet receptacles 7b are fixed on both sides by the filling material 10. Here, the connecting channels 9a, 9b and the free spaces 11 simultaneously form a flux barrier to ensure controlled guidance of the magnetic flux.

[0047] Figure 3 shows the lamella assembly 5 in a perspective view. The lamella assembly 5 has a large number of main lamellae 12 stacked one above the other in an axial direction 103 with respect to the main axis of rotation 100; these main lamellae 12 are the most numerous and constitute a large part of the lamella assembly 5.

[0048] Furthermore, the lamellar assembly 5 has at least two limiting intermediate lamellae 13, which limit the filling mass 10 (not shown) on both axial sides of the lamellar assembly 5 in the axial direction with respect to the main axis of rotation 100. For this purpose, at least one of the limiting intermediate lamellae 13 is arranged within the lamellar assembly 5 between two adjacent main lamellae 12 at a distance 105 from an axial end face in an axial direction 103, in order to limit the filling channels 9a, 9b and thus the filling mass 10 in the axial direction 103. Furthermore, at least one of the limiting intermediate lamellae 13 is spaced at a distance 106 from the other axial end face within the lamella package 5 between two adjacent main lamellae 12 in an axially opposite direction 104 in order to limit the filling channels 9a, 9b and thus the filling mass 10 in the axially opposite direction 104.

[0049] The distances 105, 106 are less than the total length of the lamellar pack 5. For example, the distances 105, 106 are less than 50 mm and / or less than 10% of the total length of the lamellar pack 5. For example, the distances 105, 106 can be the same or different from each other. Depending on the injection pressure and lamellar thickness, one limiting intermediate lamellar 13 per side may be sufficient. However, if the injection pressure is so high that the filler material 10 deforms the limiting intermediate lamellar 13 too much, then several limiting intermediate lamellar 13 can also be used axially one behind the other.

[0050] The lamellar assembly 5 further comprises at least one limiting end lamella 14, which limits the filling material 10 (not shown) on at least one axial side of the lamellar assembly 5 in the direction of the outer circumference. For this purpose, the at least one limiting end lamella 14 is arranged in the axial direction 103 at the axial end face of the lamellar assembly 5, adjacent to a main lamella 12, in order to limit the open magnet receptacles 7a and thus the filling material 10 in the axial direction 103. As shown, the limiting end lamella 14 can only be positioned on one end face. However, the filling process of the filling material 10 is more reliable if the limiting end lamella 14 is arranged on both end faces.

[0051] Furthermore, the lamella package 5 comprises at least two clamping lamellae 15 for clamping the permanent magnets 8 in the respective magnet receptacle 7a, 7b, and at least two bending edge lamellae 16 cooperating with the clamping lamellae 15 to form a bending edge for the clamping lamellae 15.

[0052] Here, the axial direction 103 defines a mounting direction for the permanent magnets 8, with the bending edge lamellae 16 arranged in the axial direction 103 after their respective clamping lamellae 15. The number of bending edge lamellae 16 and clamping lamellae 15 depends on the desired clamping force. These two lamella types can also be combined with the previously described limiting lamellae 13, 14 to reduce the number of different special lamellae.

[0053] Figure 4 shows the rotor 3 in a perspective view, with the main lamellae 12, the clamping lamellae 15, and the bending edge lamellae 16 graphically suppressed. It can be seen that two permanent magnets 8 are arranged one behind the other in the axial direction 103 in each magnet holder 7a, 7b. It is also possible to install only one permanent magnet 8 or many permanent magnets 8 bonded together in the respective magnet holder 7a, 7b.

[0054] The permanent magnets 8 are fixed only at their end faces by the filling material 10 in the respective magnet receptacles 7. For this purpose, the filling material 10 is poured into the corresponding filling channels 9a, 9b on both sides and prevented from flowing further by the limiting intermediate lamellae 13, so that the area of ​​the filling channels 9a, 9b axially between the two limiting intermediate lamellae 13 is not filled with the filling material 10. With further optimization, the permanent magnets 8 can always be fixed from both sides by means of the filling material 10 up to a corresponding limiting intermediate lamella 13.

[0055] Figure 5 shows a single main lamella 12 in an axial view with respect to the main axis of rotation 100. The main lamella 12 has six receiving openings 17 per rotor pole 4, each of which has a magnet receiving section 18 to form the magnet receptacles 7a, 7b and at least one filling channel section 19a, 19 adjacent to the magnet receiving section 18 to form the filling channels 9a, 9b.

[0056] The outer receiving openings 17a have a free space section 20 open towards the outer circumference to form the free spaces 11, which borders the magnet receiving section 18 on a narrow side opposite the filling channel section 19a. Thus, the outer receiving openings 17a are designed as receiving openings 17a open towards the outer circumference.

[0057] The central receiving openings 17b have a further filling channel section 19b to form the further filling channels 9b, which adjoins the magnet receiving section 18 on a narrow side opposite the filling channel section 19a. Thus, the central receiving openings 17b are designed as closed receiving openings 17b.

[0058] Furthermore, the receiving openings 17a, 17b each have two spaced-apart retaining elements 21 on one broad side for fixing the position of the respective permanent magnet 8 in the corresponding magnet receiving section 18. The retaining elements 21 are arranged in the area between the magnet receiving section 18 and the respective filling channel section 19a, 19b or the free space section 20. In other words, the magnet receiving section 18 and the filling channel section 19a, 19b or the free space section 20 are defined by the retaining elements 21.

[0059] Figure 6 shows a single intermediate limiting lamella 13 in an axial view with respect to the main axis of rotation 100. The intermediate limiting lamella 13 is essentially identical in construction to the main lamella 12, except that the intermediate limiting lamella 13 has reduced receiving openings 17a, 17b in cross-sectional area. The intermediate limiting lamella 13 has a magnet receiving section 18 for each magnet receptacle 7, with material sections 22a, 22b directly adjoining the magnet receiving section 18 instead of filling channel sections 19a, 19b. In other words, the material sections 22a, 22b, viewed axially with respect to the main axis of rotation 100, overlap the respective filling channel sections 19a, 19b of the main lamellae 12 in order to axially limit the respective filling channel 9a, 9b. The material sections 22a, 22b are arranged in place of the holding elements 21.

[0060] The open receiving openings 17a each have a free space section 20 to form the free spaces 11. This free space section adjoins the magnet receiving section 18 on a narrow side opposite the material section 23a and is arranged congruently with the free space sections 20 of the main lamellae 12. The magnet receiving sections 18 of the closed receiving openings 17b, on the other hand, are bounded on both sides on the narrow sides by the material sections 22a and 22b.

[0061] Figure 7 shows a single limiting end lamella 14 in an axial view with respect to the main axis of rotation 100. The limiting end lamella 14 is essentially identical in construction to the main lamella 12, except that the limiting end lamella 14, unlike the main lamella 12, has exclusively closed receiving openings 17b. If a lamella pack 5 with open magnet receptacles 7a for fixing the permanent magnets 8 is filled with the filling material 10, the filling material 10 may leak out undefined at the outer circumference.

[0062] The limiting end lamella 13 therefore has a web section 23 on its outer circumference, which directly abuts the magnet receiving section 18 of the outer receiving openings 7 and limits the magnet receiving section 18 towards the outer circumference and / or separates it from the free space section 21. The web sections 23 serve to seal the free space 11 so that the filling material 10 cannot escape at the outer circumference. The web sections 23 are arranged here in place of the retaining elements 21. In particular, the web sections 23 are electromagnetically optimized and very thin, which reduces the disadvantage of magnetic resistance. Furthermore, depending on the lamella thickness used and the height tolerance between the permanent magnet 8 and the lamella stack 5, only a very small number of limiting end lamellae 13 are required, which further reduces the negative influence of the web sections 23.

[0063] Figure 8 shows a single clamping lamella 15 in an axial view with respect to the main axis of rotation 100. The clamping lamella 15 is essentially identical in construction to the main lamella 12, except that, unlike the main lamella 12, the clamping lamella 15 has a clamping element 24 for each receiving opening 17. This clamping element 24 is arranged on an inner broad side of the magnet receiving section 18 and serves to clamp and fix the permanent magnet 8 in the respective magnet receptacle 7. The clamping elements 24 are formed as clamping tabs projecting into the receiving opening 17, which are bent over at the bending edge of the subsequent flexed-edge lamella 15 when the permanent magnets 8 are inserted. The clamping element 24 thereby presses the respective permanent magnet 8 against the radially outer broad side of the magnet receiving section 18. This ensures that the permanent magnets 8 do not break due to the high centrifugal force that occurs at high rotor speeds.

[0064] Furthermore, the clamping lamella 15 has web sections 23 on its outer circumference, which directly adjoin the magnet receiving section 18 of the outer receiving openings 7. In contrast to the limiting end lamella 14, the web sections 23 serve only to stiffen the clamping lamella 15 in order to prevent the receiving openings 17 from bending open when the permanent magnets 8 are inserted. The web sections 23 are arranged in place of the retaining elements 21, as with the limiting end lamella 14, and / or are identical in design to the web sections of the limiting end lamella 14. Figure 9 shows a single bending edge lamella 16 in an axial view with respect to the main axis of rotation 100.The bending edge lamella 16 is essentially identical in construction to the main lamella 12, wherein, unlike the main lamella 12, the bending edge lamella 16 has a recess 25 defining the bending edge in each receiving opening 17, which is arranged on an inner broad side of the magnet receiving section 18 instead of the clamping element 24 of the clamping lamella 15 and serves to at least partially receive the clamping element 24 of an adjacent clamping lamella 15.

[0065] The recess 25 defines the position (bending edge) at which the clamping element 24 is bent by inserting the permanent magnet 8. The recesses 25 are each formed by a notch or cutout, which essentially create a negative contour of the clamping element 24 when deformed in the axial direction 103 under compressive force. Depending on the sheet thickness and length of the clamping elements 24, a certain number of bending edge lamellae 16 are required after the clamping lamella 15.

[0066] Alternatively, the intermediate limiting lamella 13 and / or the end limiting lamella 14 can also be equipped with the clamping elements 24 of the clamping lamella 15 or the recesses 25 of the bending edge lamella 25. This reduces the number of special lamellae required.

[0067] Figure 10 shows a perspective view of a rotor pole 4 of the lamella stack 5. It can be seen that the magnet receptacles 7a, 7b and the adjacent filling channels 9a, 9b are formed by stacking the individual sheet metal lamellae 12, 13, 14, 15, 16 on top of each other in the axial direction 103. The magnet receptacle sections 18 are arranged congruently with each other and thus form a continuous magnet receptacle 7 in the axial direction. Likewise, the filling channel sections 19a, 19b are arranged congruently with each other, being bounded or interrupted in the axial direction 103 by the material sections 22a, 22b.

[0068] Furthermore, it can be seen that the opened magnetic receptacles 7a are on the axial

[0069] The end face is bounded by the limiting end lamella 14 in the direction of the outer circumference by the web sections 23. With permanent magnets 8 inserted, as shown in Figure 2, the filling material 10 is injected, for example, in the axial direction 103 into the filling channels 9a, 9b, whereby the filling material 10 completely fills the filling channels 9a, 9b up to the material sections 22a, 22b and the magnet receptacles 7a, 7b at least at the end face up to the web section 23. For this purpose, the permanent magnets 8 can be slightly offset inwards in the axial direction 103 relative to the limiting end lamella 14.

[0070] Furthermore, the material sections 22a and 22b can extend to the respective permanent magnet 8, forming a tolerance gap 26 as shown in Figure 2. This gap serves to compensate for tolerances between the magnet receptacle 7 and the permanent magnet 8. This simplifies the insertion of the permanent magnet 8 into the magnet receptacle 7. The tolerance gap 26 is dimensioned such that it forms a gap seal for the filling material 10 together with the permanent magnet 8. Thus, the cavity is adequately sealed.

[0071] Figure 11 shows the shape of the filling material 10 defined by the lamellar assembly 5. It can be seen that the filling material 10a of the open magnet receptacles 7a and the filling material 10b of the closed magnet receptacles 7b extend over the entire axial end face of the permanent magnets 8, thus fixing them in the axial direction. Furthermore, it can be seen that the filling material 10a of the open magnet receptacles 7a fills the cavity only on one side up to the limiting intermediate lamella 13, whereas the filling material 10b of the closed magnet receptacles 7b fills the cavity on both sides up to the limiting intermediate lamella 13.

[0072] A rotor 3 is thus proposed in which the filler material 10 is separated from the remaining cavities, particularly the flow barriers, from a certain axial length within the lamella stack 5. This allows, for example, an injection molding process or any other method, a portion of the filling channels 7 or the flow barriers to be reliably and completely filled with the filler material 10, thereby preventing void formation or frozen melt. It is thus possible to fix the permanent magnets 8 firmly in all spatial directions on at least one side. The special feature here is that the magnet fixation is enabled in a very long lamella stack 5 without requiring any skewing, thus not limiting the length of the lamella stack 5 or the rotor 3. This means that in the prior art, rotor lamination stacks are typically used in PSMs, which are stacked offset by a few degrees on the axis of rotation.Furthermore, it is no longer necessary to fully heat the lamellar package 5, which makes the process of overmolding the permanent magnets 8 more cost-effective and energy-efficient.

[0073] Reference mark

[0074] Electric machine

[0075] stator

[0076] rotor

[0077] Rotor poles a, b pole halves

[0078] Louver package

[0079] Wave recording a, b Magnetic recordings

[0080] Permanent magnets a, b Filling channels 0 Filling material 0a Filling material (open magnet receptacle) 0b Filling material (closed magnet receptacle) 1 Free spaces 2 Main lamellae 3 Intermediate limiting lamella 4 End limiting lamella 5 Clamping lamella 6 Bending edge lamella 7a, b Receptacle openings 8 Magnet receptacle section 9a, b Filling channel sections 0 Free space section 1 Retaining elements 2a, b Material sections 3 Web section 4 Clamping element 5 Recess 6 Tolerance gap 00 Main axis of rotation a, b Pole edges Pole center Axial direction Axial opposite direction Distance Further distance

Claims

Patent claims 1. Rotor (3) for an electric machine (1 ), - with several rotor poles distributed in a circumferential direction (4), - with at least one permanent magnet (8) per rotor pole (4), - with at least one lamella pack (5), wherein the lamella pack (5) has several main lamellae (12) stacked in an axial direction (103) with respect to a main axis of rotation (100), wherein the main lamellae (12) each have at least one receiving opening (17a, 17b) per rotor pole (4), each of which has a magnet receiving section (8) for forming a magnet receptacle (7a, 7b) for the permanent magnet (8) and at least one laterally adjoining filling channel section (19a, 19b) for forming a filling channel (9a, 9b), - with a filling mass (10) which is arranged at least sectionally in the respective filling channel (9a, 9b) to fix the permanent magnets (8) in the respective magnet receptacle (7a, 7b), characterized in that the lamella pack (5) has at least one limiting intermediate lamella (13) which is arranged within the lamella pack (5) spaced apart in the axial direction (103) at a distance (105) from an axial end face, wherein the filling mass (10) is limited in the axial direction (103) by the limiting intermediate lamella (13).

2. Rotor (3) according to claim 1 , characterized in that the at least one limiting intermediate lamella (13) per rotor pole (4) has at least one reduced receiving opening (17a, 17b) which has a magnet receiving section (18) for forming the magnet receiving (7a, 7b), wherein at least one material section (22a, 22b) adjacent to the magnet receiving section (18) is arranged to axially limit the filling mass (10) overlapping the filling channel section (19a, 19b) of the main lamellae (12).

3. Rotor (3) according to claim 2, characterized in that the material sections (22a, 22b) of the limiting intermediate lamella (13) extend to the respective permanent magnet (8) forming a tolerance gap (26), wherein the tolerance gap (26) is dimensioned such that it forms a gap seal for the filling mass (10).

4. Rotor (3) according to one of the preceding claims, characterized in that at least one receiving opening (17a, 17b) of the main lamellae (12) per rotor pole (4) has a further filling channel section (19b) opposite the filling channel section (19a) and laterally adjacent to the magnet receiving section to form a further filling channel (9b), wherein the further filling channel (9b) is filled with the filling mass (10) in the axial direction (103) up to the limiting intermediate lamella (13).

5. Rotor (3) according to claim 4, characterized in that the at least one limiting intermediate lamella (13) has a further material section (22b) opposite the material section (22a) and laterally adjacent to the magnet receiving section (18) for axially limiting the filling mass (10), wherein the further material section (22b) is arranged overlapping with the further filling channel section (9b) of the main lamellae (12).

6. Rotor (3) according to one of the preceding claims, characterized in that the filling mass (10) completely fills the filling channel (9a) and / or the further filling channel (9b) within the distance (105, 106) up to the at least one limiting intermediate lamella (13).

7. Rotor (3) according to one of the preceding claims, characterized in that at least one receiving opening (17a) of the main lamellae (12) per rotor pole (12) has a free space section (20) opposite the filling channel section (19a) and laterally adjacent to the magnet receiving section (18) to form a magnet-free free space (11), wherein the free space sections (20) are open in the direction of an outer circumference of the lamella pack (5).

8. Rotor (3) according to claim 7, characterized in that the free spaces (11 ) are free of filling material (10).

9. Rotor (3) according to one of the preceding claims, characterized in that the lamella pack (5) has at least one limiting end lamella (14) which is arranged in the axial direction (103) on the axial end face of the lamella pack (5), wherein the filling mass (10) is limited in the direction of an outer circumference of the lamella pack (5) by the limiting end lamella (14).

10. Rotor (3) according to claim 9, characterized in that the limiting end lamella (14) has at least one receiving opening (17a, 17b) per rotor pole (4), which has a magnet receiving section (18) for forming the magnet receiving (7a, 7b) and at least one filling channel section (19a) adjoining it laterally for forming the filling channel (9a), wherein a web section (23) opposite the filling channel section (19a) and adjoining the magnet receiving section (8) for limiting the filling mass (10) is arranged overlapping with the magnet receiving section (18) and / or the free space section (20) of the main lamellae (12).

11. Rotor (3) according to claim 9 or 10, characterized in that the limiting end lamella (14) has at least one free space section (20) adjoining the web section (23) for each rotor pole (4) to form the magnet-free free space (11), wherein the magnet receiving section (18) and the free space section (20) are separated from each other by the web section (23).

12. Rotor (3) according to one of the preceding claims, characterized in that the lamella pack (5) has at least one clamping lamella (15) for clamping fixation of the permanent magnet (9) in the magnet receptacle (8) and / or at least one bending edge lamella (16) for forming a bending edge for a clamping element (24).

13. Rotor (3) according to one of the preceding claims, characterized in that the intermediate limiting lamella (13) and / or the end limiting lamella (14) each have at least one clamping element (24) for clamping the permanent magnet (9) in the respective magnet receptacle (7a, 7b) or a recess (25) for forming a bending edge for the clamping element (24).

14. Rotor (3) according to one of the preceding claims, characterized in that the rotor poles (4) each have a pole center (102) which divides the respective rotor pole (4) into two pole halves (4a, 4b), wherein in each pole half (4a, 4b) at least one magnet receptacle (7a, 7b) and at least one adjacent filling channel (9a, 9b) are arranged which are mirror-symmetrical with respect to the pole center (102).

15. Electric machine (1 ) with the rotor (3) according to one of the preceding claims.

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