Rotor

Abstract

Rotor of an electric machine, in particular an electric motor or generator with - a basic body (3) comprising a central axis (5), which - two end faces (9,9') and - has a circumferential surface (7) lying between these, having at least two recording areas (13), and - with at least two magnets (11) provided on the circumferential surface (7) and arranged in the at least two receiving areas (13), preferably permanent magnets, wherein - the base body (3) has at least one cavity (17), wherein - the at least two magnets (11) are formed in an essentially U-shape with an inner contour facing away from the central axis (5), wherein - the base body (3) has at least two strips of material (29) engaging in the at least two magnets (11), which span the at least two receiving areas (13), and wherein - the base body (3) is produced using an additive manufacturing process or a metal powder injection molding process.

Description

[0001] The invention relates to a rotor of an electrical machine, in particular an electric motor or a generator according to the preamble of claim 1.

[0002] Rotors of the type discussed here are known. They comprise a base body with a circumferential surface on which at least two magnets are provided. It has been found that electrical machines such as electric motors or generators with rotors of the type discussed here are excessively heavy. In many cases, particularly in areas where a large number of electric motors are used, for example as actuators in motor vehicles and the like, or in the field of automation technology, it is desirable to minimize the weight increase caused by the number of electric motors. In many applications, very small motors are required, which have correspondingly small magnets; the production of such motors is very time-consuming and costly. A known rotor is disclosed in JP 2005-45 978 A. This rotor, in particular, has a structure similar to a finger crown with magnets arranged thereon.A similar rotor is also disclosed in DE 11 2007 000 129 T5. DE 10 2006 049 825 A1 discloses a rotor with recesses and external magnets, with the magnets clamped between inserts. Such a rotor is also disclosed in DE 10 2013 101 957 A1. DE 87 18 128 U1 discloses a device for the powder-metallurgical production of molded bodies by laser sintering.

[0003] The object of the invention is therefore to provide a rotor of an electrical machine, in particular an electric motor or generator, which avoids these disadvantages.

[0004] To achieve this object, a rotor is proposed which has the features of claim 1. It comprises a base body with a central axis, which has two end faces and an intermediate circumferential surface on which at least two magnets, in particular permanent magnets, are provided. The base body of the rotor is characterized in that it is manufactured by means of an additive process or a metal powder injection molding process. Such processes are characterized in that the structure of the base body of the rotor, in particular also its interior, can be freely selected within a wide range, with the additive processes mentioned here being characterized in that they are comparatively inexpensive. In particular, it is possible to produce a base body that is very lightweight. This is achieved in that the base body has at least one cavity.The production of such a base body is much simpler and cheaper than is the case with conventional processes, especially with machining processes.

[0005] A particularly preferred embodiment is characterized in that the base body has an outer wall region forming the circumferential surface, which on the one hand gives the base body external stability and on the other hand serves to influence the field lines of the at least two magnets in such a way that they have an optimal course.

[0006] A further preferred embodiment is characterized in that the base body has a wall section running in the direction of the central axis, which receives or forms an axis for supporting the rotor. This wall section can, for example, be designed as a tube running between the end faces of the base body and arranged coaxially to the central axis. It is also possible to provide tube sections, or at least two tube sections, running along the central axis. These can accommodate a continuous axis or axis sections arranged in the region of the end faces, so that the rotor can rotate when used in an electric motor or generator. It is also conceivable to continue the wall section running in the direction of the central axis beyond the end faces, so that the wall section itself forms the axis of the rotor, around which the rotor can rotate.The areas of the wall section that protrude beyond the end faces can be hollow or solid.

[0007] In a further preferred embodiment, at least one web extends between the wall region and the wall section, which holds the wall region and the wall section in a predetermined position relative to each other. This design allows the rotor to be realized with a very low weight.

[0008] A further preferred embodiment is characterized by a number of webs extending between the wall region and the wall section, with a hollow space arranged between two adjacent webs. This design still results in a low weight of the rotor, but provides its base body with increased stability.

[0009] A preferred embodiment of the rotor is also characterized in that the webs run between the two end faces and are implemented either continuously or as web sections. In this case, it is preferably possible to arrange the ends of the webs offset from one another by a particularly small angle of rotation, so that the webs, even when designed as web sections, are arranged along an imaginary helical line. This configuration results in the rotor being ventilated internally during rotation because the helical webs transport air from one end face to the other, thus dissipating the heat inside the base body.

[0010] Another embodiment of the rotor is preferred because a receiving area is created in the circumferential surface for each of the at least two magnets. The at least two magnets are therefore not simply placed on the surface and secured there, but are inserted into the receiving areas, so that they are partially recessed into the outer wall area or its circumferential surface. This ensures that the magnets have a particularly good hold on the rotor, allowing it to operate even at very high speeds.

[0011] A further preferred embodiment of the rotor is one in which the receiving areas are formed as a groove, preferably closed at its ends, which is U-shaped, triangular, or trapezoidal in shape to ensure a positive connection between the magnets inserted into the groove and the rotor. The magnets are thus held particularly securely on the rotor.

[0012] Particularly preferred is also an embodiment of the rotor which is characterized in that the base body is formed in two or more parts. This makes it possible to insert the at least two magnets, preferably a number of magnets, in particular permanent magnets, into the receiving areas of one sub-element of the base body and then to connect the other sub-element to the first sub-element. The base body is thus divided into at least two parts, the contact surface of which is, for example, perpendicular to the central axis. Of course, it is also possible to realize a contact surface that is at an angle to the central axis.If the base body has more than two parts, at least one intermediate element can be inserted between the two sub-elements of the base body having the end faces of the base body. The length of the intermediate element, measured in the direction of the central axis, can vary, so that rotors of different sizes can be easily realized. Several intermediate elements of the same size can also be inserted between the two sub-elements with the end faces of the base body in order to realize rotors of different lengths. It is therefore easy to provide a modular system for the realization of rotors of different sizes. Preferably, the sub-elements are provided with an electrically insulating intermediate layer or coating on their contact surfaces in order to minimize the occurrence of eddy current losses.

[0013] Finally, a particularly preferred embodiment of the rotor is characterized by the use of additive processes, also known as generative processes, to create the base body, such as laser sintering, FDM (fused deposit modeling), stereolithography, electron beam welding, and inkjet 3D printing. It is also possible to produce the rotor using the MIM process (metal injection molding).

[0014] The invention is explained in more detail below with reference to the drawings. They show: Fig. 1 a side view of a first embodiment of a rotor, Fig. 2 a front view of the rotor according to Fig. 1, Fig. 3 a sectional view of the rotor according to Fig. 1 without magnets, Fig. 4 an exploded view of the first embodiment of the rotor, Fig. 5 an exploded view of a second embodiment of a rotor and Fig. 6 a sectional view of the rotor according to Fig. 5 with magnets.

[0015] Fig. 1 shows a side view of a first exemplary embodiment of a rotor 1 of an electrical machine, in particular an electric motor or generator, which rotor comprises a base body 3 with a central axis 5, a circumferential surface 7, and two end faces 9, 9'. At least two magnets 11, preferably permanent magnets, are provided on the circumferential surface 7 of the rotor 1. The exemplary embodiment of the rotor 1 shown here has a total of eight magnets running parallel to the central axis 5, which do not quite reach the end faces 9, 9'. In principle, it is possible to attach the at least two magnets 11 to the circumferential surface 7, for example, by gluing them. Preferably, however, the at least two magnets are each accommodated in a receiving area 13, which is preferably designed as a groove formed in the circumferential surface 7.In principle, it is provided that each of the at least two magnets is assigned a receiving area 13, or preferably is designed as a groove. As mentioned, the at least two magnets 11 do not extend to the end face 9, 9' of the base body 3. Accordingly, it is preferably provided that the at least two receiving areas 13 do not extend to the end face 9, 9'.

[0016] Fig. 1 that the base body 3 is preferably constructed in several parts and has at least two sub-elements. Here, it has two sub-elements 3a and 3b, whose contact surfaces 15a and 15b are aligned perpendicular to the central axis 5. However, it is also conceivable for the contact surfaces 15a and 15b to form an angle with the central axis 5. Furthermore, the contact surfaces can also have complementary structures and interlock with one another, for example radially extending ribs and depressions. However, it is particularly easy to realize a base body 3 whose sub-elements 3a and 3b have contact surfaces 15a and 15b running perpendicular to the central axis 5. In order to minimize the occurrence of eddy current losses, an intermediate layer or coating is preferably provided at the contact points between two sub-elements.

[0017] The base body 3 is characterized by the fact that it is manufactured using an additive process, also known as a generative process. Such processes allow for the simple and cost-effective creation of receiving areas 13 that are groove-shaped and have a U-, triangular, or trapezoidal cross-section. This makes it easy to create a positive connection between the base body 3 and the at least two magnets 11 using such an additive process. The internal structure of the base body 3 can also be very lightweight, which will be discussed in more detail below.

[0018] The following additive processes are preferred: laser sintering (SLS or selective laser sintering), FDM (fused deposit modeling), stereolithography, electron beam welding and / or inkjet 3D printing.

[0019] Furthermore, it is also possible, especially for high volumes, to manufacture the base body 3 of the rotor 1 using the metal powder injection molding process, i.e., the metal injection molding (MIM) process. In contrast, the three-dimensional inkjet printing process is preferable, especially for small volumes.

[0020] Fig. 2 shows the Fig. 1, viewed from one end face. The end face 9 is shown here. Identical parts are provided with the same reference numerals, so reference is made to the previous description.

[0021] The end face view shows that the base body 3 of the rotor 1 comprises at least one cavity 17. In the embodiment shown here, a total of eight cavities are provided, which are perpendicular to the image plane of Fig. 2 and extend parallel to the central axis 5. Preferably, the number of cavities 17 is adapted to that of the magnets 11.

[0022] The base body 3 has an outer wall region 19 which runs in the direction of the central axis 17 and forms the peripheral surface 7, which also serves as the outer boundary of the at least one cavity 17 and which also forms the peripheral surface of the base body 5.

[0023] It can be seen that the wall region 19 is preferably contoured, i.e., has a contour which serves to concentrate the course of the field lines 21 forming between two magnets 11, shown here in dashed lines, and to minimize stray losses when the rotor 1 is used in an electric motor or a generator. For this reason, the wall region 19 between two adjacent magnets 11 has a greater thickness than is the case, for example, in the center of a magnet 11. Close to the central axis 5, a wall section 23 is provided which runs in the direction of the same and serves to receive or form an axis of the rotor 1 about which the rotor can rotate. For this purpose, the wall section 23 is designed as a tube running in the direction of the central axis 5.It is also conceivable to form a solid body running along the central axis 5, but the tubular design is preferable because this leads to a reduction in the weight of the base body 3. The wall section 23 can also have a number of tubular sections arranged in the direction of the central axis 5 and spaced from one another.

[0024] Finally, it is possible to extend the wall section 23 beyond the end faces 9, 9', so that these extensions then serve as the axis of rotation for the rotor 1. If necessary, the last areas of the wall section 23, in particular those that protrude beyond the end faces 9, 9', can also be designed as solid bodies in order to be able to absorb higher loads.

[0025] The one from Fig. The rotor 1 shown in Figure 2 has a base body 5 which has at least one web 25 running between the outer wall region 19 and the wall section 23 running in the direction of the central axis 5. This web connects the wall region 19 and the wall section 23. With a corresponding design of the web, it may be sufficient to actually provide only one web between the wall region 19 and the wall section 23. This leads to a significant reduction in weight. Particularly at higher speeds of the rotor 1 when used in an electric motor or generator, it is preferably provided to provide more than one web 25. In the embodiment shown here, eight webs 25 are provided. However, with a corresponding load on the rotor 1, three could also be sufficient. As soon as more than one cavity 17 is provided, more than two webs 25 must also be provided to separate the cavities from one another.It should be noted that a tight separation of the cavities by the webs is not necessary. It is therefore possible to provide individual web sections with gaps in between in the direction of the central axis 5 to further reduce the weight of the base body. Accordingly, the inner wall section 23, as mentioned, can also consist of sections running in the direction of the central axis 5.

[0026] In principle, continuous webs or a number of consecutive webs in the direction of the central axis are preferably provided between the end faces 9 and 9'. In particular, it is preferably provided that the start of a web 25, for example on the end face 9, is rotated relative to the end of the web, for example on the end face 9', in order to create a web that runs along an imaginary helical line. In the interior of the base body 3, the at least one web 25 thus creates a helix which, when the base body 3 or rotor 1 rotates, conveys air through the base body 3, so that heat generated inside the base body 3 when the rotor 1 is used in an electric motor or generator is dissipated.

[0027] The offset of the beginning of a web in the area of ​​one end face compared to the end in the area of ​​the opposite end face should not be chosen to be too large, because for stability reasons the webs preferably start at the wall area 19 where it has the greatest thickness.

[0028] Fig. Figure 3 shows the rotor 1 shown in front view in cross section. However, here the at least two magnets 11, here the eight in Fig. The magnets shown in Figure 2 have been omitted. Identical parts are provided with the same reference numerals, so reference is made to the previous description.

[0029] The front view serves to explain in more detail the at least one receiving area 13 provided for the at least two magnets 11: In principle, it is possible to place the at least two magnets 11 on the circumferential surface 7 of the base body 3 and to fasten them there, be it by gluing or the like. However, it is preferably provided that a receiving area 13 is provided for each magnet 11, which is realized as a recess, i.e. as a groove that extends from the circumferential surface 7 inwards towards the central axis 5 of the base body 3. In principle, it is possible to design the grooves to be rectangular, i.e. with a bottom surface that is delimited by side walls that run parallel or radially to the central axis 5. With such a configuration, the receiving areas 13 are characterized in that they encompass a larger area of ​​a magnet 11 than would be the case if the magnet were placed on the circumferential surface 7.This results in a better connection between the magnets and the rotor or its base body than would be the case if they were simply glued on.

[0030] Preferably, therefore, a positive connection is provided between the base body 3 and the at least two magnets 11, which prevents the magnets 11 from lifting off the base body 3 or from the outer wall region 19. This is preferably achieved by an undercut, wherein the two side walls delimiting a receiving region 13 designed as a groove extend at an angle to the bottom surface of the receptacle 13, which tapers outwards, i.e., at a greater distance from the central axis 5. The grooves are therefore preferably triangular or trapezoidal in shape in order to securely anchor a magnet to the base body 3.

[0031] It is of course preferably provided that the inner contour of a receiving area 13 given in the sectional view present here is designed to be complementary to the outer contour of a magnet 11, at least in the area in which the latter is accommodated in the receiving area 13, i.e. in a groove shown here.

[0032] Even when implementing the form-fitting arrangement mentioned here through an undercut, it is preferably provided that the at least two magnets 11 are additionally glued or soldered to the base body 3. However, this is not mandatory.

[0033] The at least two receiving areas 13 on the base body 3 extend, as Fig. 1, not over its entire length. Rather, they end, like the magnets 11 housed in the receiving areas 13, at a distance from the end face 9 or 9'. This also fixes the magnets 11 in the longitudinal direction of the base body 3, i.e., in the direction of its central axis 5.

[0034] Fig. 4 shows the rotor 1 according to Fig. 1 in exploded view. Identical parts are provided with the same reference numbers, so reference is made to the previous description.

[0035] It is clearly visible that the rotor 1 has a base body 3, which comprises the two sub-elements 3a and 3b. These are arranged at a distance from one another here, with the at least two magnets 11 being inserted into the corresponding receiving areas 13 in the right-hand sub-element 3b, for example. The at least two magnets 11, here the eight magnets, extend beyond the contact surface 15b of the sub-element 3b parallel to the longitudinal axis 5 in the direction of the first sub-element 3a. The receiving areas 13 are clearly visible in the perspective exploded view, the number of which is adapted to the number of magnets 11. The at least two magnets 11 inserted into the receiving areas 13 of the right-hand sub-element 3b are inserted into the corresponding receiving area 13 of the other sub-element 3a when the base body 3 is assembled. Fig. 4 it can be seen that at the end of the receiving areas 13, a wall section 27 is provided which serves as a stop and prevents the at least two magnets 11 from being pushed out beyond the end face 9. Similarly, on the opposite side, a wall section 27' can be seen which serves as a right stop for the at least two magnets 11. After assembling the sub-elements 3a and 3b of the base body 3, the Fig. 1 shows the assembly state: The at least two magnets 11, in this case the eight magnets, are securely fixed to the base body 3 and cannot be radially dislodged even at high speeds. In the axial direction, they are securely held by the wall sections 27 and 27' on the base body 3.

[0036] The two sub-elements 3a and 3b are connected to one another in a suitable manner, for example by fastening elements running through the base body 3 in the direction of the central axis 5, for example by at least one screw, which is preferably insulated from the sub-elements. However, it is also conceivable, after the base body 3 has been placed on an axis, to attach fixing elements to the right and left side surfaces 9 and 9' of the axis. These fixing elements prevent lateral deflection, i.e. in the direction of the central axis 5, and firmly hold the two sub-elements 3a and 3b together. It is also conceivable to incorporate clamping elements into the peripheral surface 7, which firmly connect the two sub-elements 3a and 3b. Finally, it is also conceivable to incorporate pins into the contact surfaces 15a and 15b, which pins lie in corresponding bores and serve to connect the two sub-elements 3a and 3b.The pins can be fixed by gluing, soldering or the like.

[0037] For the basic idea of ​​designing the base body 3 in at least two parts, as can be seen from the exploded view according to Fig. As can be seen from Figure 4, the type of connection between the two sub-elements 3a and 3b is not important.

[0038] Based on the exploded view according to Fig. 4, it is pointed out that the base body 3 can also have more than two sub-elements 3a and 3b. For example, it is conceivable to insert at least one intermediate element between the two sub-elements 3a and 3b, which has an identical outer surface or circumferential surface to the sub-elements 3a and 3b. It is therefore possible to provide at least one continuous magnet extending from one sub-element, for example, from sub-element 3a, across the at least one intermediate piece to the second sub-element 3b.

[0039] Furthermore, it is possible to provide at least one, preferably several, magnets that do not extend over the entire length of the two sub-elements and the intermediate piece. It is conceivable to use two sub-magnets instead of a single continuous magnet, and, for example, to provide the contact surface of the two sub-magnets in some areas in the area of ​​the intermediate piece. The contact surface of two sub-magnets can also be provided in other areas of the base body 3.

[0040] The decisive factor is that the fact that the base body 3 comprises at least two parts and, if necessary, at least one intermediate element can also be used enables a modular design, which allows the length of the rotor 1 to be adapted to different electric motors or generators. It is also possible to design the sub-elements 3a and 3b with different lengths, measured in the direction of the central axis 5, in order to achieve greater variability in the length of the base body 3 of a rotor 1.

[0041] Fig. 5 shows an exploded view of a second embodiment of a rotor 1. Here, too, identical and functionally identical parts are provided with the same reference numerals, so that reference is made to the description above.

[0042] The rotor 1 shown here also has a base body 3, which in this case comprises two sub-elements 3a and 3b. The basic structure of the base body 3 is also identical to that of the first embodiment. Therefore, the differing design features will be discussed in more detail to clarify the differences.

[0043] In the case of the Fig. 1 to 4, at least two magnets, here eight magnets for example, were used, which are inserted into corresponding receiving areas 13, which realize an undercut. The at least two in Fig. The magnets 11 shown in Fig. 5 are essentially U-shaped, wherein the base of the U preferably follows a circular arc section and the legs of the U are directed slightly outwards and enclose an angle with each other which increases outwards, i.e. with greater distance from the central axis 5.

[0044] The receiving areas 13, which are adapted to the number of magnets 11, are designed accordingly and preferably have a base following a circular arc and two side walls enclosing an angle, wherein here, as in the first embodiment, the at least two receiving areas 13 are aligned parallel to the longitudinal axis 5.

[0045] Fig. 5 shows that the base body 3 has at least two material strips 29, each spanning a receiving area 13. Preferably, the number of material strips 29 is matched to the number of receiving areas 13. Furthermore, it is preferably provided that the material strips 29 extend in the direction of the receiving areas 13, in this case parallel to the central axis 5. The material strips 29 originate from the end faces 9, 9' and preferably run over the entire length of the receiving areas 13 of a sub-element 3a, 3b.

[0046] The material strips 29 are arranged and designed such that they engage with the at least two magnets 11, preferably with all magnets 11, in order to securely anchor them to the base body 3. The inner contour of the material strips 29, facing the central axis 5, is adapted to the inner contour of the U-shaped magnets 11 facing away from the central axis 5, resulting in a good contact and thus a secure hold of the magnets.

[0047] To ensure a secure hold of the at least two magnets even at higher rotational speeds of the rotor 1, it is preferably provided that the end faces of the material strips 29, which are provided on both the first sub-element 3a and the second sub-element 3b, are coupled to one another. For example, holes can be provided into which pins are inserted. The pins are long enough to span the contact surfaces 15a and 15b of the sub-elements 3a and 3b when the two sub-elements 3a and 3b are assembled.

[0048] Finally, Fig. 6 the second embodiment of the Fig. 5 shown rotor 1 with at least two magnets 11, here with eight magnets 11, in a sectional view, wherein the cutting plane, as in Fig. 3, arranged perpendicular to the central axis 5. Identical parts are provided with the same reference numerals, so reference is made to the previous description.

[0049] From the sectional view, as well as from the exploded view according to Fig. 5, it can be seen that the basic structure of the base body 3 of the second exemplary embodiment of the rotor corresponds to that of the first exemplary embodiment. The base body 3 thus has an outer wall region 19, which forms the circumferential surface 7 of the base body 3 and which is connected via at least one web 25 to an inner wall section 23 located in the region of the central axis 5. In this exemplary embodiment, it is also possible to design the webs in a helical shape in order to effectively dissipate heat generated inside the rotor 3 when used in an electric motor.

[0050] In the second embodiment of the rotor 1, the at least two receiving areas 13 in the base body 3 are not designed to create an undercut. The side walls of the receiving areas 13 are therefore not inclined toward each other, but rather extend away from each other in a quasi-V-shape, resulting in an outward-opening angle.

[0051] Despite this design of the receiving areas 13, the magnets 11 are held there, namely by the above-mentioned material stiffener 29, which engages in the free space of the U-shaped magnets 11. These have, as can be seen from Fig. As explained in Figure 5, the magnet 11 has two side walls 11a and 11b that are aligned in a V-shape and connected by a base section 11c. The material strip 29 extends over this base section 11c and thus securely holds the magnet 11 to the base body 3 of the rotor.

[0052] The length of the side walls 11a and 11b is selected so that in the second embodiment according to the Fig. 5 and Fig. 6 slightly project beyond the peripheral surface 7 of the base body 3. The thickness of at least two magnets 11, here the eight magnets 11, which are arranged in the Fig. 1, Fig. 2 and Fig. 3, is also chosen so that here too the magnets 11 protrude slightly beyond the circumferential surface 7.

[0053] The advantage of the U-shaped magnets 11, which are in the Fig. 5 and Fig. 6, is that these magnets have two adjacent north and south poles, formed by the side walls 11a and 11b. Both poles of the magnets 11 shown here are therefore usable.

[0054] In the first embodiment, the magnets 11 have an outer first pole and an inner second pole facing the central axis 5, wherein the poles S and N alternate between adjacent magnets.

[0055] Even in the embodiment according to the Fig. 5 and Fig. 6, the outer wall region 19 is contoured to focus the field lines of the magnets. As in the first embodiment, sections of the wall region 19 have a greater thickness. Here, too, the webs 25 are attached there, as is the case in the first embodiment.

[0056] Overall, it can be seen that the construction of the rotor 1, in particular the internal structure of the base body 3, can be designed using the additive manufacturing process, but also using the MIM process, in such a way that the weight of the base body 3 can be significantly reduced compared to conventionally manufactured bodies. At least one cavity 17 is provided. When using a metal powder injection molding process, the metal powder preferably comprises copper, in particular it consists of copper. The base body 3 according to the invention is significantly easier to manufacture than is the case with conventional machining processes. Furthermore, complex structures, for example the helical webs 25, can be created much more easily.In this case, it is also particularly easy to design the outer wall region 19 in such a way, in particular to realize it with different thicknesses, that the field lines of the magnets 11, which are preferably designed as permanent magnets, are optimally concentrated. In this case, it is also possible, in particular, to provide the at least one web 25 with a barrier for the magnetic flux. For this purpose, a hole 31 can be provided in the transition region between a web 25 and a thicker section of the wall region 19, which can be realized in both embodiments of the rotor. In . Fig. 6 shows the hole 31 as an example, which is used in all transition areas between a

[0057] Web 25 and the outer wall area 19. It should be noted again that such holes 31 can be easily and cost-effectively realized using additive processes.

Claims

[1] Rotor of an electrical machine, in particular an electric motor or generator with - a base body (3) comprising a central axis (5), - two front surfaces (9.9') and - a peripheral surface (7) lying between them and having at least two receiving areas (13), and - with at least two magnets (11), preferably permanent magnets, provided on the peripheral surface (7) and arranged in the at least two receiving areas (13), wherein - the base body (3) has at least one cavity (17), wherein - the at least two magnets (11) are substantially U-shaped with an inner contour facing away from the central axis (5), wherein - the base body (3) has at least two material strips (29) engaging in the at least two magnets (11) which span the at least two receiving areas (13), and wherein - the base body (3) is manufactured by means of an additive process or metal powder injection molding process. [2] Rotor according to claim 1, characterized by that the base body (3) has an outer wall region (19) forming the peripheral surface (7), which is preferably contoured. [3] Rotor according to claim 1 or 2, characterized by that the base body (3) has a wall section (23) running in the direction of the central axis (5) which receives or forms an axis of the rotor (1). [4] Rotor according to one of the preceding claims, characterized by that at least one web (25), preferably a plurality of webs (25), runs between the wall region (19) and the wall section (23), the cavity (17) being arranged between two adjacent webs (25). [5] Rotor according to claim 3 or 4, characterized bythat the at least one web (25) runs between the two end faces (9,9') and is preferably arranged along an imaginary helical line. [6] Rotor according to claim 1, characterized by that the at least two receiving areas (13) are designed as a groove that is preferably closed at its ends. [7] Rotor according to claim 1 or 6, characterized by that the at least two material strips (29) span the at least two receiving areas (13) in the longitudinal direction. [8] Rotor according to one of the preceding claims, characterized by that the rotor (1) is designed in two or more parts, so that a base body (3) divided in the longitudinal and / or transverse direction is realized, and that the partial elements of the rotor (1) are provided with an electrically insulating intermediate layer or coating on their contact surfaces. [9] Rotor according to claim 1, characterized bythat a laser sintering, FDM, stereolithography, electron beam welding and / or an inkjet printing process and / or a metal powder injection molding process can be used as an additive process.

Images