Rotor for an electrical reluctance machine

Abstract

Rotor (10) for a synchronous reluctance machine (58), comprising a laminated core (12) which has a plurality of magnetizable laminations (16) arranged successively in the direction of a rotational axis (14) of the rotor (10), which laminations have a lamination geometry with flux-conducting sections (18) and flux-blocking sections (20) for a magnetic flux, wherein the flux-conducting sections (18) and flux-blocking sections (20) are formed by lamination openings (22) in the laminations (16), and wherein the lamination openings (22) of the laminations (16) are aligned with one another in the axial direction to the rotational axis (14) in order to form axial through-openings (24) of the laminated core (12), characterized in that the rotor (10) is designed without a rotor shaft in that the laminations (16) are designed without a central lamination opening for receiving a rotor shaft, and a coupling unit (26) with at least one coupling element (28),which projects at least partially into at least one of the through openings (24), wherein the coupling unit (26) is designed to connect a drive shaft.,

Description

[0001] The invention relates to a rotor for a synchronous reluctance machine, comprising a laminated core having a plurality of magnetizable laminations arranged consecutively in the direction of a rotational axis of the rotor, said laminations having a lamination geometry with flux-conducting sections and flux-blocking sections for a magnetic flux. The flux-conducting sections and flux-blocking sections are formed by lamination openings in the laminations, and the lamination openings in the laminations are aligned with one another in the axial direction relative to the rotational axis in order to form axial through-openings in the lamination core. Furthermore, the invention relates to a reluctance machine having a stator and a rotor arranged so as to be rotatable relative to the stator. Finally, the invention also relates to a motor vehicle having a rotating electrical machine.

[0002] Rotors, magnetic units of rotors, rotating electrical reluctance machines, and motor vehicles are extensively known in the prior art, so that, in principle, separate written documentation is not required. Generic rotating electrical machines are not only, but now frequently, used in electrically powered motor vehicles, such as hybrid vehicles, electric vehicles, or the like, in the area of a respective drive system. Furthermore, they can be used not only in the drive system of the motor vehicle, but also in other drive functions, for example, in a window lift, a starter motor, and / or the like.

[0003] The rotating electric machine can be designed as either an internal rotor or an external rotor. In an electrically powered motor vehicle, the rotating electric machine often serves to drive the motor vehicle during normal driving operation. However, it can also be used for other drive functions, such as a window lift, an oil and / or water pump, and / or the like.

[0004] A rotating electrical machine is a device that converts electrical energy into mechanical energy, particularly kinetic energy in the form of rotation, in motor mode, and / or mechanical energy into electrical energy in generator mode. This movement is usually a rotational movement performed by the rotor relative to the stator. Unlike the rotor, the stator is usually non-rotatably mounted, meaning the rotational movement is a rotational movement of the rotor relative to the stator.

[0005] The stator and rotor are linked by a magnetic flux, which in motor operation creates the force, namely the torque, which drives the rotor to rotate relative to the stator. In generator operation, however, mechanical energy supplied to the rotor can be converted into electrical energy in the form of torque. For this purpose, at least the stator and possibly also the rotor usually have a magnetic unit, which in turn can generally comprise a winding through which an electric current flows. In the stator or the rotor, the winding can also at least partially contain permanent magnets or at least be supplemented by permanent magnets. This differs from the reluctance machine, which is a special design of a rotating electrical machine. As a rule, the rotor has neither permanent magnets nor a rotor winding.However, the magnetic unit of the rotor of the reluctance machine provides preferred directions for guiding the magnetic flux. Using the reluctance principle, torque can be generated. A synchronous reluctance machine is a reluctance machine with a multiphase stator winding. The stator winding is supplied with a multiphase electric current, creating a rotating magnetic field on the stator side. During normal operation, the rotor rotates with this magnetic field.

[0006] An electric reluctance machine is an electrical machine in which the driving effect is achieved primarily through the use of a reluctance force, or a Maxwell force. This force can be generated by changing the magnetic resistance and is to be distinguished from the Lorentz force, which is used to generate torque in conventional rotating electrical machines. In addition to reluctance machines, especially synchronous reluctance machines, transverse flux machines also utilize this principle.

[0007] The synchronous reluctance machine is usually designed as a multi-phase rotating electrical machine. This means that the stator of the electrical machine has a correspondingly designed multi-phase stator winding. In contrast, the rotor of the electrical machine is windingless and usually also permanent magnet-free. Instead, the rotor has a laminated core, which can have a plurality of magnetizable laminations arranged consecutively in the direction of a rotational axis of the rotor, which have a lamination geometry with flux-conducting sections and flux-blocking sections for guiding the magnetic flux. The flux-conducting sections and the flux-blocking sections are formed or designed by lamination openings in the laminations. The lamination openings in the laminations are preferably aligned with one another in the circumferential direction relative to the rotational axis, thus forming axial through-openings in the lamination core.During normal operation, the rotor rotates synchronously with a rotating magnetic field provided by the multi-phase winding of the stator, as in conventional rotating electrical synchronous machines.

[0008] A rotor core is disclosed, for example, by DE 102 07 267 A1, which discloses a rotor for a rotating electrical machine, specifically a reluctance motor. This teaching is directed to stabilizing the rotor core against the action of centripetal forces during the rotor's rotation. For this purpose, EP 3 160 014 A1 teaches that the core openings should be filled with material. At the same time, the rotor should be able to be designed as a squirrel-cage rotor, for example, to enable self-starting. For this purpose, EP 3 160 014 A1 teaches that the core openings are filled with a material that is not ferromagnetic but electrically conductive. Furthermore, the core openings can also partially contain an insulating resin. In this context, DE 102 07 267 A1 discloses a rotor for a synchronous reluctance motor and its manufacturing method.Furthermore, DE 696 00 160 T2 discloses an armature for a reluctance machine.

[0009] Even though this teaching has proven itself in the prior art, there is still room for improvement. For example, the laminations have a central through-hole so that a through-hole in the laminated core can be provided for a rotor shaft. In this way, the laminated core is connected to the rotor shaft, preferably providing a rotationally fixed connection between the laminated core and the rotor shaft. However, this design limits the formation of the flux-conducting and flux-blocking sections in the individual laminations of the laminated core. This also limits the drive function of the synchronous reluctance machine, particularly with regard to the provision of torque and efficiency.

[0010] The invention is based on the object of providing an improved construction for a rotor of the synchronous reluctance machine, by means of which an improved effect of the synchronous reluctance machine can be achieved.

[0011] As a solution, the invention proposes a rotor, a reluctance machine and a motor vehicle according to the independent claims.

[0012] Advantageous further training results from features of the dependent claims.

[0013] With regard to a generic rotor, the invention proposes in particular that the rotor is designed without a rotor shaft and has a coupling unit with at least one coupling element which projects at least partially into at least one of the through openings, wherein the coupling unit is designed, preferably at least on one end face of the laminated core, for connecting a drive shaft.

[0014] With regard to a generic reluctance machine, the invention proposes in particular that it has a rotor according to the invention.

[0015] With regard to a generic motor vehicle, the invention proposes in particular that the rotating electrical machine is designed according to the invention.

[0016] The invention is based, among other things, on the idea that the principle of the reluctance machine is based on an anisotropy of the magnetic conductivity in the rotor. The torque of a reluctance machine, especially a synchronous reluctance machine, can be determined, for example, from machine data according to the following formula: M=k[1Lq−1Ld]ψ2sin2δ

[0017] In the formula, k denotes a machine constant, whereas L q and L dInductances in a q-direction and a d-direction, Ψ denotes a magnetic flux and δ a rotor angle. From the above formula it follows that for a large torque a ratio of L d / L q should be as large as possible. Therefore, the greater the flux guidance in the d-direction that can be achieved and the more the magnetic flux in the q-direction can be limited, the greater the torque that can be achieved with the synchronous reluctance machine.

[0018] This means that increasing a substantially radial extent of the sheet openings in the q-direction and maintaining the radial extent of the flux guide sections in the d-direction can enable a larger torque, where L q smaller and L d can remain constant. The ratio of L d to L qis therefore larger. However, this design is not possible in the prior art because the available space for providing the flux-conducting sections and the flux-blocking sections is limited radially outwards by the radius of the rotor or the laminated core. In the prior art, an inner limitation is created by the central opening in the laminations that accommodates the rotor shaft. This means that for a given radius of the rotor shaft, there is an optimal radial extension of the lamination openings in order to be able to provide the maximum possible torque. Both a larger and a smaller radial width would simply reduce the torque.

[0019] A further concept of the invention is to eliminate the central openings in the laminations used to pass through the rotor shaft and to utilize the space thus provided to more effectively design the flux-conducting and flux-blocking sections. This makes it possible to increase the extent of the flux-blocking sections, particularly in the q-direction, thereby significantly improving flux guidance in the d-direction and, consequently, increasing the torque of the synchronous reluctance machine during normal operation. The rotor is therefore advantageously designed without a rotor shaft.

[0020] To enable coupling of the rotor to a drive shaft in this design, the invention provides a coupling unit comprising at least one coupling element that extends at least partially into at least one of the through-openings of the laminated core. This allows the coupling element to mechanically couple the rotor and transmit torque.

[0021] Furthermore, the coupling unit is designed to connect the drive shaft at least on one end face of the laminated core. The coupling unit thus provides a connecting element by means of which the coupling unit can be connected to the drive shaft, in particular in a rotationally fixed manner. This allows torque to be transmitted from the rotor to the drive shaft and vice versa.

[0022] The coupling unit is preferably designed substantially symmetrically with respect to the rotor's rotational axis. Therefore, the coupling unit preferably has a plurality of coupling elements that engage in corresponding, in particular mutually different, through-openings in the laminated core. This allows for a good, reliable connection between the rotor and the drive shaft. A drive shaft or rotor shaft extending through the rotor can thus be eliminated. The invention therefore also allows for cost savings in this regard.

[0023] In essence, the coupling element takes over the part of the rotor shaft in the rotor area, which in state-of-the-art electrical machines extends through the laminated core. The coupling element makes it possible to eliminate the need for a rotor shaft extending through the laminated core. The corresponding connection between the laminated core and the drive shaft, which is to be rotationally fixedly coupled to the rotor, is realized by the coupling unit. Avoiding the central hole in the rotor laminated core allows for greater freedom in the design of the flux-conducting sections and the flux-blocking sections. In particular, the laminated core openings can be made larger than in the prior art, so that, as can be seen from the above formula, the available torque can also be increased with otherwise identical dimensions. This can then also increase the efficiency.

[0024] According to an advantageous development, it is proposed that the coupling element at least partially fills the through-opening in the radial direction and / or in the circumferential direction. This makes it possible to ensure that the coupling element at least partially rests against a wall of the sheet metal opening, and thus a force can be transmitted in the circumferential direction between the wall of the sheet metal opening and the coupling element. For this purpose, the coupling element is designed to be at least partially adapted to a shape of the wall of the sheet metal opening or the through-opening of the laminated core. Particularly advantageously, the coupling element is designed such that it completely fills the through-opening of the laminated core or the respective sheet metal opening. This makes it possible to achieve particularly favorable force transmission between the coupling element and the laminated core. The coupling element can extend over the entire axial length of the laminated core.For this reason, the coupling element only needs to extend partially in the axial direction into the through-opening of the laminated core.

[0025] The coupling unit preferably comprises a plurality of coupling elements that can engage in respective through-openings of the laminated core or sheet metal openings. Preferably, one coupling element engages in each respective through-opening of the laminated core or sheet metal opening. However, it can also be provided that several coupling elements engage in each respective through-opening of the laminated core. In this way, the coupling element can be designed in the manner of a cage or a partial cage.

[0026] The coupling unit preferably has a plurality of coupling elements and at least one first connecting element, wherein the coupling elements are arranged spaced apart from one another in the circumferential direction and in respective through-openings, and wherein the coupling elements are mechanically firmly connected to the first connecting element at least at one respective end. This makes it possible to create an integral coupling unit which is preferably formed in one piece. For example, the coupling unit can be manufactured cost-effectively in this way by injection molding or a comparable manufacturing process. The first connecting element can be, for example, a connecting plate which can be arranged on the end face of the rotor or laminated core, a connecting ring or the like. A screw, a rivet, an adhesive and / or the like can be used to connect the coupling elements to the first connecting element, preferably depending on the material.Alternatively or additionally, a connection technique such as welding, soldering, or the like can also be provided. The first connecting element can be used to mechanically connect the coupling unit to the drive shaft, particularly in a rotationally fixed manner.

[0027] According to a further development, it is proposed that a coupling unit is arranged at each of the opposite end faces of the rotor or the laminated core, wherein the two coupling units are connected to one another by means of at least one second connecting element arranged in the through-opening. The second connecting element thus serves to connect the two opposite coupling units to one another. The connecting element can be formed by an armature, a through-bolt formed in a longitudinal opening of respective coupling elements arranged opposite one another in a respective through-opening, or the like. The second connecting element can basically be made of the same material as the coupling unit. However, a different material suitable for the application can also be used.

[0028] The coupling unit preferably comprises a non-magnetizable or diamagnetic material. This also applies in particular to the first and / or second connecting elements as well as further connecting elements, if present. By selecting such a material, the function of the flux-conducting sections and the flux-saving sections, which are determined by the sheet metal openings in the sheets, can be maintained essentially unchanged. In particular, if a diamagnetic material is used, the function of the flux-conducting sections and the flux-saving sections can even be improved. The material used can be, for example, stainless steel, a plastic, in particular a fiber-reinforced plastic, a composite material, for example in the form of a ferrite, a ceramic, or the like. The material preferably has poor electrical conductivity.

[0029] If a material is used that has electrical conductivity, the at least one coupling element can be designed to be at least partially layered in the axial direction, wherein the layers are preferably designed to be electrically insulated from one another. As a result, as with the laminated core, the formation of eddy currents during normal operation can be reduced. This is particularly advantageous if the at least one coupling element or the coupling unit is arranged in the region of an outer radius of the laminated core. If, on the other hand, the coupling unit is only designed in the region of the center of the laminated core, such a structure does not need to be provided because the effect of magnetic fields that form eddy currents is generally very small there, for example negligible.

[0030] Preferably, the material thus has a low electrical conductivity and / or is at least partially layered in the axial direction of the axis of rotation.

[0031] According to a further embodiment, it is proposed that the coupling unit be arranged with respect to the axis of rotation at a radius that is smaller than approximately 70%, preferably smaller than approximately 55%, particularly preferably smaller than approximately 45% of a radius of the laminated core. This has the advantage that the coupling unit is only exposed to a reduced centripetal force during normal operation of the electrical machine. This allows the design of the coupling unit to be more cost-effective and compact. Furthermore, the electrical conductivity of the coupling unit does not need to be particularly low because, as already explained above, significant alternating magnetic fields are no longer to be expected in this area. This allows the coupling unit to be designed to be particularly robust.

[0032] According to a further development, it is proposed that a cross-sectional contour of the at least one coupling element be adapted, at least in the circumferential direction, to a cross-sectional contour of the through-opening. This ensures that the coupling element at least partially abuts the cross-sectional contour of the through-opening, thus allowing the torque or force to be transmitted over a comparatively large area. A good force transmission effect between the rotor or the laminated core and the coupling element or the coupling unit can be achieved.

[0033] The advantages and effects stated for the rotor according to the invention naturally apply equally to the rotating electrical machine equipped with the rotor according to the invention and to the motor vehicle equipped with the rotating electrical machine according to the invention and vice versa.

[0034] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0035] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0036] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a schematic perspective view of a coupling unit for a rotor of a synchronous reluctance machine, which can be arranged on an end face of a laminated core of a rotor of the reluctance machine; Fig. 2 a schematic exploded view of the rotor according to Fig.1, in which on each of its opposite end faces a coupling unit according to Fig. 1 is arranged; Fig. 3 a schematic perspective side view of one of the end faces of the rotor according to Fig. 2; Fig. 4 a schematic view as Fig. 3, in which a sector is cut out of the rotor; Fig. 5 a schematic sectional view of the rotor according to Fig. 3 along a longitudinal axis; Fig. 6 a schematic diagram illustrating an effect of the rotor design according to Fig. 2 compared to the state of the art; Fig. 7 a schematic sectional view of the rotor according to Fig. 3 transverse to the longitudinal axis; Fig. 8 an enlarged schematic representation of a sector VIII from Fig. 7; Fig. 9 a schematic representation of how Fig.8, where the magnetic field is shown in normal operation; Fig. 10 a schematic comparison of the sector according to Fig. 8 in relation to a corresponding sector of a prior art rotor; Fig. 11 a schematic diagram of a torque-speed characteristic of the Fig. 10 opposing runners; Fig. 12 a schematic diagram of a dependence of efficiency on speed and torque in a comparison as Fig. 11; and Fig. 13 shows a schematic side view of an electrically driven motor vehicle with an electric drive device comprising a synchronous reluctance machine.

[0037] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0038] In the figures, the same reference symbols designate elements with the same function.

[0039] Fig.13 shows a schematic side view of an electrically driven motor vehicle, which here is embodied as an electric vehicle 50. The electric vehicle 50 has an electric drive device 52, which includes a rotating electric machine 58 for driving the electric vehicle 50 in a normal driving mode. The rotating electric machine 58 is embodied here as a multiphase synchronous reluctance machine. The electric drive device 52 is further connected via a multiphase inverter 56 as an energy converter to a high-voltage battery 54, which serves to supply electrical energy to the drive device 52.

[0040] Fig. 1 shows a schematic perspective view of a coupling unit 26 for a rotor 10 for a synchronous reluctance machine 58 ( Fig. 8, Fig. 9, Fig. 10).

[0041] The rotor 10 is shown in a schematic exploded view in Fig. 2. From Fig. 2 it can be seen that the rotor 10 comprises a laminated core 12 with a plurality of magnetizable sheets 16 ( Fig. 7). The magnetizable sheets 16 have a substantially circular outer circumference. The sheets 16 are arranged electrically insulated from one another, so that a layered structure is achieved in the axial direction of the rotation axis 14. Fig. 3 shows the rotor 10 in a schematic perspective side view of one of its end faces 30 in the assembled state. Fig. 4 shows a schematic view of how Fig. 3, in which a sector is cut out of the rotor 10 so that the arrangement of the coupling unit 26 on the laminated core 12 can be seen. Fig. 5 shows a schematic sectional view of the rotor 10 according to Fig.3 along a cutting plane which is determined by the axis of rotation 14 as the longitudinal axis. Fig. 7 shows a schematic plan view of one of the laminations 16 of the laminated core 12 of the rotor 10 according to Fig. 3 transverse to the longitudinal axis or rotation axis 14. The other sheets 16 are essentially identical.

[0042] From the aforementioned figures, it can be seen that each lamination 16 has a lamination geometry with flux-conducting sections 18 and flux-blocking sections 20 for a magnetic flux during normal operation of the synchronous reluctance machine 58. The flux-conducting sections 18 and the flux-blocking sections 20 are formed by lamination openings 22 in the laminations 16. In the sequential arrangement of the laminations 16, they are aligned with one another in the axial direction relative to the rotational axis 14 such that axial through-openings 24 of the lamination stack 12 are formed. This forms a rotor 10 suitable for the synchronous reluctance machine 58 with a correspondingly suitable lamination stack 12.

[0043] From the Fig.1 to 5 and 7, it is clear that the rotor 10 does not have a rotor shaft. Furthermore, the rotor 10 also does not have permanent magnets. Thus, the rotor 10 is not designed with permanent magnet excitation. Rather, the synchronous reluctance motor 58 utilizes the principle of reluctance force through preferred directions determined by the flux-conducting sections 18 and the flux-blocking sections 20. The operating principle of the reluctance motor is known to those skilled in the art, which is why no further explanations will be provided.

[0044] Because the rotor 10 is designed without a rotor shaft, it is necessary to provide a mechanical connection to the rotor 10 for a drive shaft not shown in the figures. This is made possible by the coupling unit 26 ( Fig. 1), which in the present embodiment according to Fig.2 two are provided, which are arranged at the opposite front ends 30 of the laminated core 12 or the rotor 10.

[0045] Fig. 1 shows that the coupling unit 26 comprises coupling elements 28, each of which is fastened at a respective end to a connecting plate 32 as the first connecting element. The coupling elements 28 are designed to partially fill the respective through-opening 24 of the laminated core 12 in the radial direction and in the circumferential direction ( Fig. 7) and to protrude at least partially into these through-openings 24. For this purpose, the coupling elements 28 have correspondingly adapted cross-sections. Furthermore, the coupling elements 28 are arranged at a suitable distance from one another in the circumferential direction so that they can each be inserted into different ones of the through-openings 24. In the present case, each coupling element 28 is arranged in one of the through-openings 24.

[0046] In the present embodiment, the coupling units 26 are arranged from opposite ends of the rotor 10 or the laminated core 12 such that their coupling elements 28 are inserted into the respective through-openings 24. The length of the coupling elements 28 in the present embodiment is selected such that the connecting plates 32 can rest against the respective end faces 30 of the laminated core 12 or the rotor 10. This may also vary in alternative embodiments.

[0047] As can be seen from the Fig.As can also be seen in Figures 2 to 5 and 7, the coupling elements 28 as well as the connecting plates 32 have bores 36 that serve to receive threaded pins 34 as second connecting elements. The threaded pins 34 extend through the coupling elements 28 and the connecting plates 32 and provide projecting threaded pins onto which nuts 38 are screwed. This allows a firm connection of the coupling units 26 to the laminated core 12 and thus to the rotor 10 to be achieved.

[0048] Furthermore, the Fig. 2 to 5 show that each coupling unit 26, with its connecting plate 32, provides a connecting flange 40 facing away from the respective end face 30, which can be coupled to the drive shaft. In this way, the rotor 10 can be coupled to a respective drive shaft in order to achieve the desired drive function by the synchronous reluctance machine 58.

[0049] In the present embodiment, the coupling unit 26 is formed from a non-magnetizable or diamagnetic material. In the present embodiment, the material is stainless steel. In alternative embodiments, another suitable material can of course also be used, for example, a plastic or the like. However, the material is preferably a poor electrical conductor, preferably an electrical insulator.

[0050] It can also be seen in the figures that, in the present exemplary embodiment, an outer diameter of the coupling unit 26 with respect to the rotational axis 14 is smaller than approximately 70% of the diameter of the laminated core 12. In alternative embodiments, however, the diameter of the coupling unit 26 with respect to the laminated core 12 can also be smaller, for example, less than approximately 55% or even less than approximately 45%.

[0051] In the present embodiment, it is further provided that the connecting elements 32, 34, 38 are part of the coupling unit 26. In alternative embodiments, however, they can also be separate parts. In particular, in alternative embodiments, it can be provided that the respective coupling unit is connected to the laminated core 12 in a manner other than or in addition to threaded pins and nuts. For example, a press connection, an adhesive connection, a welded connection, or the like can be provided here. Of course, combinations of these can also be provided.

[0052] Fig.Figure 6 shows, in a schematic comparison, how the invention can be used to enlarge the lamination openings 22, so that the efficiency of the synchronous reluctance machine 58 can be increased. The left-hand illustration shows a lamination opening 22 with respect to its radial width according to the prior art. Visible in the left-hand area is a laminated core 12 connected to a rotor shaft 42, which is why the laminations 16 of this laminated core 12 have a central through-opening in which the rotor shaft 42 is arranged. Consequently, the width of the lamination openings 22 in the radial direction is B1.

[0053] Opposite in the right area of the Fig.Figure 6 shows a laminated core 12 according to the invention. As can be seen from this illustration, the rotor 10 here does not have a rotor shaft. This allows the width of the lamination openings 22 to be increased in the radial direction, so that a width B2 can be achieved. The width B2 is significantly larger than the width B1, which allows a greater torque to be achieved with the same magnetic flux or the same magnetic field. This will be explained further with reference to the following figures.

[0054] Fig.Figure 8 shows a radial sectional view of a sector of the synchronous reluctance machine 58. It can be seen that the synchronous reluctance machine 58 is designed as an internal rotor. For this purpose, the synchronous reluctance machine 58 provides a stator 60, which has a stator core (not designated) with a stator winding (also not designated). The stator winding is designed for three-phase operation at a corresponding alternating voltage. In alternative embodiments, the stator winding can, of course, also be designed for more than three phases.

[0055] The rotor 10 is rotatably mounted within a substantially circular stator opening provided by the rotor 60. The rotor 10 is spaced from the stator 60 by an air gap 44.

[0056] It can be seen that the runner 10 according to the Fig.1 to 5 and 7. Regarding the further features, reference is therefore made to the corresponding explanations for these figures.

[0057] Fig. 9 now shows a representation like Fig. 8, but in which magnetic field lines of a magnetic flux are shown during intended operation. It can be seen that the magnetic flux is essentially guided through the flux-conducting sections 18. In contrast, the flux-blocking sections 20 ensure that the magnetic flux in these areas is only very weak. The flux-blocking sections 20 thus cause the magnetic flux to be concentrated in the flux-conducting sections 18.

[0058] Fig. 10 shows once again a comparison of the sectors according to Fig. 9 compared to corresponding sectors of the state of the art. The comparison corresponds to that already established on the basis of Fig.6, which is why reference is made to the relevant explanations. Fig. 10 shows that the left-hand section shows a sector of a synchronous reluctance machine 58 of the prior art, in which the sheet metal opening 22 has the radial width B1. In the right-hand illustration of the Fig. 10 shows a corresponding illustration according to the invention, from which it can be seen that the radial width of the sheet metal opening 22 is B2. However, B2 is significantly larger than B2. The relevant effects of the larger radial width of the sheet metal openings 22 are illustrated by a schematic diagram of a torque-speed characteristic curve according to Fig. 11 shown.

[0059] Fig. 11 shows a graph 46 showing a torque curve M1 as it is generated with the synchronous reluctance machine 58 according to the left illustration in Fig.10 is achieved. A second graph 48 shows the corresponding curve of a torque M2, as it is achieved with the synchronous reluctance machine 58 according to the invention according to the right-hand illustration in Fig. 10 is achieved. It can be seen that, with the same magnetic flux, a significantly greater torque can be achieved with the inventive design compared to the prior art design. The inventive design allows a ratio of L d to L q can be significantly increased, which also allows a correspondingly increased torque to be achieved with the same magnetic flux. As a result, the efficiency of the synchronous reluctance machine 58 can also be increased overall by the invention.

[0060] By increasing the radial width of the sheet metal openings 22, that is, in the q-direction, and maintaining the cross-section for the magnetic flux in the d-direction, it is possible to increase the torque because the inductance L q becomes smaller, but at the same time the inductance L d remains essentially constant. The invention achieves this by providing increased space for forming the sheet metal openings 22 because the central sheet metal opening of the sheets 16 in the prior art can be omitted. According to the invention, the rotor 10 no longer has a rotor shaft, so that additional space is available for forming the sheet metal openings 22 and thus the flux blocking sections 20. Thus, essentially the entire cross-sectional area of the sheets 16 in the radial direction is available for forming the flux-conducting sections 18 and the flux blocking sections 20.

[0061] Fig. 12 shows a further schematic diagram in which a dependence of the efficiency of the synchronous reluctance machine 58 on the speed and the torque in a comparison as Fig. 11. In Fig. In Figure 12, a graph 70 shows an efficiency contour of the synchronous reluctance machine 58 according to the prior art. A graph 72 shows the corresponding efficiency contour of the synchronous reluctance machine 58 according to the invention. Graph 74 also shows a torque of the synchronous reluctance machine 58 according to the invention, whereas a graph 76 shows the corresponding torque for the synchronous reluctance machine 58 of the prior art. It can be seen that, particularly in the field-weakening range, the torque of the synchronous reluctance machine 58 according to the invention can be significantly increased compared to the prior art.

[0062] The synchronous reluctance machine 58 according to the invention can exhibit greater torque and better efficiency, especially at higher torques, compared to a corresponding synchronous reluctance machine 58 according to the prior art, even if all boundary conditions, such as electrical power supply, maximum voltage, maximum current, rotor diameter, stator including stator winding, and the like, are essentially the same. The following tables illustrate this further. Table 1 shows the effect on torque, whereas Table 2 shows the effect on efficiency. Table 1 State of the art Invention idea Advantage of the invention idea n [1 / min] M [Nm] M [Nm] ΔM [Nm] ΔM [%] 6000 262,1 270,8 +8,7 +3,32% 8000 150,5 161,7 +11,2 +7,44% 12000 47,6 51,4 +3,8 +7,98% Table 2 State of the art Invention idea Advantage of the idea η [%] η [%] Δη [%] 94,62% 94,82% +0,20% 97,11% 97,12% +0,01 % 95,29% 95,40% +0,11 %

[0063] The embodiments serve solely to explain the invention and are not intended to limit it.

[0064] Overall, the examples show how an improved rotor can be provided for a reluctance machine.

Claims

[1] Rotor (10) for a synchronous reluctance machine (58), with a laminated core (12) which has a plurality of magnetizable laminations (16) arranged successively in the direction of a rotational axis (14) of the rotor (10), which have a lamination geometry with flux-conducting sections (18) and flux-blocking sections (20) for a magnetic flux, wherein the flux-conducting sections (18) and flux-blocking sections (20) are formed by lamination openings (22) in the laminations (16), and wherein the lamination openings (22) of the laminations (16) are aligned with one another in the axial direction to the rotational axis (14) in order to form axial through-openings (24) of the laminated core (12), characterized byin that the rotor (10) is designed without a rotor shaft in that the sheets (16) are designed without a central sheet opening for receiving a rotor shaft, and has a coupling unit (26) with at least one coupling element (28) which projects at least partially into at least one of the through openings (24), wherein the coupling unit (26) is designed for connecting a drive shaft. [2] Rotor according to claim 1, characterized by that the coupling element (28) at least partially fills the through opening (24) in the radial direction and / or in the circumferential direction. [3] Rotor according to one of the preceding claims, characterized byin that the coupling unit (26) has a plurality of coupling elements (28) and at least one first connecting element (32), wherein the coupling elements (28) are arranged spaced apart from one another in the circumferential direction and in respective ones of the through openings (24), and wherein the coupling elements (28) are mechanically firmly connected to the first connecting element (32) at least at one respective end. [4] Rotor according to one of the preceding claims, characterized by that a coupling unit (26) is arranged at each of the opposite front ends of the rotor (10), wherein the coupling units (26) are connected to one another by means of at least one second connecting element (34) arranged in the through opening (24). [5] Rotor according to one of the preceding claims, characterized by that the coupling unit (26) comprises a non-magnetizable and / or diamagnetic material. [6] Rotor according to claim 5, characterized bythat the material is stainless steel. [7] Rotor according to one of the preceding claims, characterized by that the material has a low electrical conductivity and / or is at least partially layered in the axial direction of the axis of rotation (14). [8] Rotor according to one of the preceding claims, characterized by that the coupling unit (26) is arranged with respect to the axis of rotation at a radius which is less than 70%, preferably less than 55%, particularly preferably less than 45% of a radius of the laminated core. [9] Rotor according to one of the preceding claims, characterized by that a cross-sectional contour of the at least one coupling element (28) is adapted at least in the circumferential direction to a cross-sectional contour of the through opening (24). [10] Reluctance machine (58) with a stator (60) and a rotor (10) rotatably arranged relative to the stator (60), characterized bythat the rotor (10) is designed according to one of the preceding claims. [11] Motor vehicle (50) with a rotating electrical machine (10), characterized by that the rotating electrical machine (58) is designed according to claim 10.

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