Rotor for axial flux motor and method for manufacturing a rotor for an axial flux motor

Abstract

The invention relates to a rotor (1) for an axial flux motor (28), comprising a rotor shaft (2) having a longitudinal axis (L), and a rotor module (3), which is fastened to the rotor shaft (2), the rotor module (3) comprising a plurality of permanent magnets (4) which are spaced apart from one another in the circumferential direction with respect to the longitudinal axis (L), wherein magnetic axes of the permanent magnets (4) are arranged substantially parallel to the longitudinal axis (L), wherein the rotor shaft (2) has a fastening portion (5), on the circumferential surface of which a fastening profile (6) is provided, wherein the rotor module (3) comprises a rotor body (7) which is produced from a casting compound (V), which preferably comprises epoxy resin, wherein the fastening portion (5) of the rotor shaft (2) is encapsulated by the casting compound (V) in such a way that a form-fitting connection is produced between the fastening profile (6) and the rotor body (7) at least in the circumferential direction, and wherein the permanent magnets (4) are circumferentially encapsulated by the casting compound in such a way that they are held on the rotor body (7) without further fastening means.

Description

[0001] ROTOR FOR AN AXIAL FLOW MOTOR AND METHOD FOR MANUFACTURING A ROTOR FOR AN AXIAL FLOW MOTOR

[0002] The invention relates to a rotor for an axial flux motor, comprising a rotor shaft with a longitudinal axis and a rotor module attached to the rotor shaft, wherein the rotor module comprises several permanent magnets spaced apart from one another in the circumferential direction with respect to the longitudinal axis, wherein the magnet axes of the permanent magnets are arranged substantially parallel to the longitudinal axis.Furthermore, the invention relates to an axial flux motor comprising a stator with a stator housing having a first housing half and a second housing half, and comprising a rotor with a rotor shaft rotatably mounted in the stator housing, wherein several electrical coils are arranged on the first housing half and the second housing half, and wherein several circumferentially spaced permanent magnets are provided on a rotor module of the rotor located axially between the first housing half and the second housing half, which magnetically interact with the coils of the stator to set the rotor in rotation.

[0003] Furthermore, the invention relates to a method for manufacturing a rotor for an axial flux motor.

[0004] Axial flux motors offer several specific advantages over conventional radial flux motors. They are often more efficient, especially at low speeds, making them ideal for applications such as electric vehicles. Axial flux motors have a flatter and more compact design, resulting in smaller size and lighter weight. This compact structure is particularly beneficial for applications where space is limited. Axial flux motors can generate higher torque at lower speeds, making them especially useful for applications requiring high starting torque.

[0005] Furthermore, the design of axial flux motors can lead to a reduction in manufacturing costs, as they potentially require less material and are easier to assemble. Their design allows for more efficient heat dissipation, which increases the motor's performance and lifespan. The design of axial flux motors enables their use in various configurations, opening up diverse application possibilities in different industries. These advantages make axial flux motors an attractive option for many modern technological applications, especially where efficiency, space savings, and performance are critical.

[0006] The object of the present invention was to provide a rotor for an axial flux motor that is as simple as possible in design, as well as a cost-effective method for manufacturing such a rotor.

[0007] This problem is solved with the aforementioned rotor by the fact that the rotor shaft has a mounting section with a mounting profile on its circumferential surface, that the rotor module comprises a rotor body made of a potting compound, preferably epoxy resin, wherein the mounting section of the rotor shaft is encased in the potting compound in such a way that a positive-locking connection is established between the mounting profile and the rotor body, at least in the circumferential direction, and that the permanent magnets are encased circumferentially in the potting compound in such a way that they are held on the rotor body, in particular without any further fastening means. The rotor requires minimal assembly effort, since all components are held on the rotor body by the potting compound.

[0008] The permanent magnets preferably have an even number of first magnet groups and an identical number of second magnet groups, wherein the first and second magnet groups alternate circumferentially and have opposite poles, with each first magnet group comprising at least one permanent magnet and each second magnet group comprising at least one permanent magnet. Multiple permanent magnets can also be provided per magnet group, together forming a magnetic pole. This allows the rotor to be adapted relatively easily to different predefined boundary conditions.

[0009] Permanent magnets can be one-piece or multi-piece. Multi-piece permanent magnets could, for example, be designed as segmented permanent magnets, comprising several separate magnetic segments. This allows for the production of permanent magnets of different sizes and / or shapes.

[0010] The mounting profile preferably has a toothed section and / or at least one, preferably several, of the following profiles: a recess, in particular a groove or bore; a projection, in particular a rib or pin. Alternatively or additionally, the mounting profile may have an undercut. This creates a positive-locking connection between the rotor body and the rotor shaft, enabling reliable torque transmission.

[0011] It is advantageous if the mounting section has a larger diameter than the rest of the rotor shaft and the mounting profile is axially spaced from opposite end faces of the mounting section. This prevents the potting compound from escaping axially from the mounting profile, thus simplifying the sealing process during manufacturing.

[0012] The rotor body can consist of at least 90%, preferably at least 95%, and in particular essentially entirely, of the potting compound. This may mean that small components or ingredients can be added to the potting compound, particularly to improve its strength or heat dissipation.

[0013] Preferably, the rotor body comprises a reinforcing insert, preferably non-metallic, which is preferably completely encased in the potting compound, wherein the reinforcing insert preferably lies in a plane perpendicular to the longitudinal axis, in particular a plane of symmetry, of the rotor body. This increases the operational strength, and in particular allows centrifugal forces to be absorbed more effectively. The reinforcing insert can, for example, comprise a mat or mesh of textile fibers, preferably of an aromatic polyamide, and / or a mat or mesh of a glass fiber reinforced plastic, and / or a mat or mesh of a carbon fiber reinforced plastic.

[0014] The rotor body can comprise at least one end face, preferably both end faces, a plurality of stiffening ribs spaced apart from each other in the circumferential direction and located, viewed radially, in a region between the permanent magnets and the mounting section of the rotor shaft. This increases the torsional stiffness with respect to the longitudinal axis as well as the bending stiffness with respect to a bending axis transverse to the longitudinal axis.

[0015] The rotor module preferably comprises a closed stabilizing ring located radially outside the permanent magnets, wherein the stabilizing ring is held to the rotor body, preferably exclusively, by the potting compound, and wherein the stabilizing ring is preferably encased by the potting compound at least radially outside, and in particular on all sides. This allows the centrifugal forces acting on the permanent magnets to be better supported, especially at high rotational speeds.

[0016] The stabilizing ring can be made of a metallic material, in particular aluminum, or of a non-metallic material, in particular carbon. Alternatively or additionally, the stabilizing ring could also be flexible, for example in the form of a rope or band.

[0017] The stabilizing ring can comprise several circumferentially spaced positioning projections on an inner circumferential surface, wherein each positioning projection extends radially between two circumferentially adjacent permanent magnets, particularly without contacting the permanent magnets, or each positioning projection is arranged circumferentially within the region of a permanent magnet, particularly without contacting an outer circumferential surface of the respective permanent magnet. This facilitates the positioning of the permanent magnets during manufacturing.

[0018] It is advantageous if the permanent magnets have a retaining profile on at least their circumferentially opposite outer surfaces, which is encased or cast into the potting compound in a form-fitting manner. This improves the retention of the permanent magnets on the rotor body. In particular, this is advantageous to eliminate the need for additional fasteners. Optionally, a retaining profile can also be provided on an inner and / or outer circumferential surface of the permanent magnets.

[0019] To improve the hold, it may be advantageous if the holding profile has an undercut and / or the holding profile comprises at least one, preferably several, of the following profiles: recess, in particular groove or bore; projection, in particular rib or pin.

[0020] Preferably, the rotor according to the invention is used in the axial flux motor mentioned above. This allows for a simple and therefore cost-effective axial flux motor to be provided. In a further aspect, the invention relates to a spindle drive comprising a threaded spindle, a spindle nut rotatably arranged on the threaded spindle, and a drive unit configured to rotate the spindle nut in order to move the threaded spindle axially relative to the spindle nut. The drive unit is designed as an axial flux motor according to the invention (see above). This allows for a very compact, simple, and therefore cost-effective spindle drive. The spindle drive can be used as an actuator for a wide variety of applications where linear movement or actuation is required.Due to its comparatively high torque, the spindle drive can be used, for example, as a replacement for a hydraulic cylinder or pneumatic cylinder.

[0021] To minimize friction, it is advantageous to have multiple rolling elements between the threaded spindle and the spindle nut. These rolling elements can, for example, be balls, and the threaded spindle can be a ball screw. Alternatively, the spindle drive can be a planetary roller screw drive, with the rolling elements being planetary rollers.

[0022] Preferably, the rotor shaft of the axial flux motor is designed as a hollow shaft. The hollow shaft can either simultaneously form the spindle nut or it can be connected to the spindle nut, particularly in a rotationally fixed manner. The threaded spindle extends through the hollow shaft. This allows for a relatively compact design with a comparatively long stroke.

[0023] Preferably, the rotor shaft or hollow shaft is mounted in the stator housing in such a way that not only the radial forces occurring during the operation of the axial flux motor can be absorbed, but also the axial forces acting on the threaded spindle during the operation of the spindle drive.

[0024] The problem is also solved by the aforementioned method by carrying out the following steps: providing a rotor shaft with a longitudinal axis and two shaft ends, wherein the rotor shaft includes a mounting section located between the shaft ends, on the circumferential surface of which a mounting profile is provided for attaching a rotor module; providing a mold comprising a die for producing a rotor body for the rotor module, wherein the mold comprises a first mold half with a first die section and a second mold half with a second die section, wherein the first mold half comprises a first shaft recess and the second mold half a second shaft recess; arranging the rotor shaft on the first mold half such that the mounting section is located in the area of ​​the first die section and the first shaft end is located in the first shaft recess.Positioning several permanent magnets in the area of ​​the first die section of the first mold half such that the magnetic axes of the permanent magnets are aligned essentially parallel to the longitudinal axis of the rotor shaft, the permanent magnets are spaced radially from the longitudinal axis at a defined radial distance, and adjacent permanent magnets are spaced from each other circumferentially with respect to the longitudinal axis at a defined circumferential distance; arranging the second mold half on the first mold half such that the second shaft end is located in the second shaft recess and the two die sections together form the essentially hermetically sealed die; casting the die with a casting compound by introducing the casting compound in liquid form into the die through a number of filling openings in the mold; hardening of the casting compound.Detaching the second mold half from the first mold half and removing the rotor from the mold.

[0025] The method according to the invention enables simple and cost-effective manufacturing of the rotor, as relatively few work steps are required. In particular, no further steps are necessary for mounting the permanent magnets, since the permanent magnets are encased in the potting compound. Therefore, no additional fastening elements are required.

[0026] Optionally, at least part of the die surface can be coated with a suitable coating. This coating could, for example, be a non-stick coating, such as one made of polytetrafluoroethylene. This simplifies the removal of the finished rotor.

[0027] It can be advantageous if the first shaft recess of the first mold half is designed as a through-opening connecting the first die section to an opposite outer surface, with the first shaft end extending through the through-opening. Alternatively or additionally, the second shaft recess of the second mold half can be designed as a through-opening connecting the second die section to an opposite outer surface, with the second shaft end extending through the through-opening. This allows for the production of a rotor with a longer shaft.

[0028] The permanent magnets are preferably arranged in an even number of first magnet groups and an identical number of second magnet groups, wherein the first magnet groups and the second magnet groups are arranged alternately and with opposite polarity in the circumferential direction, and wherein at least one permanent magnet is provided in each of the first magnet groups and the second magnet groups. This results in the advantages mentioned above.

[0029] It is advantageous to create a vacuum in the die before and / or during casting, particularly by means of a vacuum pump. This reduces, and preferably prevents, the risk of unwanted air inclusions forming in the rotor body. For example, one or more suction ports can be provided on the mold, leading into the die and connected to the vacuum pump.

[0030] The longitudinal axis of the rotor shaft is preferably aligned substantially vertically, at least during the positioning of the permanent magnets. Consequently, the mold is also oriented in such a way that the arrangement of the permanent magnets and any other components can take place in a substantially horizontal plane, which simplifies handling.

[0031] According to an advantageous embodiment, the permanent magnets are held in position on the first mold half by means of holding magnets. These holding magnets are arranged on the outer side of the first mold half, opposite the first die section, and exert a magnetic holding force on the permanent magnets through the first mold half. Electromagnets or permanent magnets can be used as holding magnets. After curing, the holding magnets can be removed, for example, or the holding force deactivated, to facilitate removal of the finished rotor from the mold.

[0032] It can be advantageous to arrange positioning elements on one of the end faces of the first mold half facing the die in the axial direction. Each positioning element is located, viewed circumferentially, in a region between two adjacent permanent magnets and projects axially between the adjacent permanent magnets to hold the permanent magnets in position during casting. The positioning elements are preferably arranged in a central region of the permanent magnets when viewed radially. This simplifies the positioning of the permanent magnets, as it reduces the risk of the permanent magnets' position changing undesirably due to the magnetic forces. In particular, it prevents adjacent permanent magnets from coming into contact with each other.

[0033] It is advantageous if a closed stabilizing ring is arranged radially outside the permanent magnets in the first die section of the first mold half, and is encased in the potting compound at least radially outside, preferably on all sides, so that after curing, the stabilizing ring is held to the rotor body, preferably exclusively, by the potting compound. This results in the advantages mentioned above. The potting process eliminates the need for fasteners or further steps to attach the stabilizing ring to the rotor body, thus simplifying manufacturing. For example, a ring made of a metallic material, particularly aluminum, or of a non-metallic material, particularly carbon, can be used as the stabilizing ring. Alternatively or additionally, a flexible ring, particularly a rope or band, can be used as the stabilizing ring.

[0034] The stabilizing ring can comprise several circumferentially spaced positioning projections on an inner circumferential surface. The stabilizing ring is arranged in the first mold half such that each positioning projection extends radially between two circumferentially adjacent permanent magnets, preferably without contacting the permanent magnets. Alternatively, each positioning projection is arranged circumferentially within the region of a permanent magnet, preferably without contacting an outer circumferential surface of the respective permanent magnet. This simplifies the positioning of the permanent magnets and, in particular, prevents changes in position. Furthermore, the retention of the stabilizing ring on the rotor body can be improved by overmolding the positioning projections.Preferably, the permanent magnets each have a retaining profile on at least their circumferentially opposite outer surfaces, which is encased or cast in a form-fitting manner by the potting compound. The retaining profile can, for example, have an undercut and / or comprise at least one, preferably several, of the following profiles: a recess, in particular a groove or bore; a projection, in particular a rib or pin. This results in the advantages mentioned above.

[0035] To increase the operational strength of the rotor, it can be advantageous to insert a, preferably non-metallic, reinforcing insert in the first die section, which is preferably completely surrounded by the potting compound, wherein the reinforcing insert preferably lies in a plane normal to the longitudinal axis of the rotor body, in particular a plane of symmetry, and wherein the reinforcing insert preferably consists of a mat or a mesh made of textile fibers, in particular of an aromatic polyamide, and / or a mat or a mesh made of a glass fiber reinforced plastic and / or a mat or a mesh made of a carbon fiber reinforced plastic.

[0036] Preferably, a plurality of recesses for creating stiffening ribs on the finished rotor body are provided on one end face of the first mold half facing the die in the axial direction. These recesses are spaced apart from each other in the circumferential direction and, viewed radially, are located in an area between the permanent magnets and the mounting section of the rotor shaft. This results in the advantages mentioned above.

[0037] It is advantageous to move, vibrate, and / or rotate the mold during and / or after pouring. This reduces the risk of air inclusions. Moving, vibrating, and rotating the mold can be done manually or, preferably, by means of a suitable motion device.

[0038] Preferably, the viscosity of the potting compound is reduced before or during casting by tempering it to a predetermined temperature, preferably using a tempering device. The specific temperature depends on the potting compound used and can vary. The tempering device can, for example, include a suitable hot air blower, a heated container, a (UV) lamp, or the like. Tempering by chemical processes is also conceivable. To accelerate the curing of the potting compound, it can be advantageous to heat the mold, at least partially, before, during, or after casting using a heating device.

[0039] To better understand the invention, it is explained in more detail with reference to the following figures.

[0040] They each show, in a highly simplified, schematic representation:

[0041] Fig. 1a is a top view of a rotor of an exemplary embodiment of the invention;

[0042] Fig. 11b shows a section through the rotor along the section line AA in Fig. 1a;

[0043] Fig. 2 shows a longitudinal section through an axial flux motor of an exemplary embodiment of the invention;

[0044] Fig. 3 shows a rotor shaft of the rotor and a longitudinal section through a casting mold for the

[0045] Implementation of the inventive method;

[0046] Fig. 4 shows a longitudinal section through a first half of the mold and the rotor shaft arranged thereon during the execution of the method according to the invention;

[0047] Fig. 5 shows a top view of the first half of the mold and the rotor shaft attached to it, as well as two exemplary permanent magnets in perspective view;

[0048] Fig. 6 shows a longitudinal section through the mold during the execution of further processes.

[0049] Steps of the inventive method;

[0050] Fig. 7 shows a longitudinal section through the mold during the execution of further steps of the inventive method,

[0051] Fig. 8 shows a longitudinal section through the mold during the demolding of the rotor, and Fig. 9 shows a spindle drive of an exemplary embodiment in a longitudinal section.

[0052] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0053] Reference is made first to Figs. 1a and 1b. Fig. 1 shows a rotor 1 of an exemplary embodiment of the invention in a top view. Fig. 1b shows a section through the rotor along section line AA in Fig. 1a. The rotor 1 is intended for use in an axial flux motor 28, as will be explained in more detail later with reference to Fig. 2.

[0054] The rotor 1 comprises a rotor shaft 2 with a longitudinal axis L and two opposing shaft ends 2a, 2b. The rotor 1 also includes a rotor module 3, which is attached to the rotor shaft 2. Several permanent magnets 4 are arranged on the rotor module 3, spaced apart from each other circumferentially with respect to the longitudinal axis L. The magnetic axes of the permanent magnets 4 are oriented essentially parallel to the longitudinal axis L, such that each magnetic pole (north pole N or south pole S) is located at one of the opposite end faces of the rotor module 3. The term "magnetic axis" generally refers to an imaginary axis that passes through the magnetic north and south poles.

[0055] Preferably, the multiple permanent magnets 4 comprise an even number of first magnet groups 8 and an identical number of second magnet groups 9, which alternate circumferentially and have opposite poles. Each first magnet group 8 comprises at least one permanent magnet 4, and each second magnet group 9 also comprises at least one permanent magnet 4, the number of permanent magnets 4 in each magnet group 8, 9 preferably being identical. In the illustrated example, four first magnet groups 8, each with two permanent magnets 4, and four second magnet groups 9, each with two permanent magnets 4, are provided by way of example only. Each magnet group 8, 9 forms one magnetic pole. Of course, the illustrated arrangement is only an example, and a different distribution of the permanent magnets 4 in each magnet group 8, 9 would also be possible.According to a preferred embodiment, each magnet group 8, 9 contains a single permanent magnet 4. Thus, permanent magnets 4 of opposite polarity are arranged alternately in the circumferential direction.

[0056] The rotor shaft 2 has a mounting section 5 for attaching the rotor module 3, on the circumferential surface of which a mounting profile 6 is provided. The mounting section 5 is preferably arranged centrally between the two shaft ends 2a, 2b and can, for example, have a larger diameter than the rest of the rotor shaft 2. The mounting section 5 is preferably formed integrally with the rotor shaft 2. Alternatively, the mounting section 5 could also be a separate component and be connected to a shaft to form the rotor shaft 2. In this case, the mounting section 5 could, for example, be hollow cylindrical and pressed onto the shaft or connected to the shaft by another joining process, e.g., by welding or by means of a suitable shaft-hub connection.

[0057] The rotor module 3 has a rotor body 7 made of a potting compound V. The potting compound V preferably comprises a suitable epoxy resin. The rotor body 7 preferably consists of at least 90%, more preferably at least 95%, and in particular essentially entirely of the potting compound V. Optionally, the potting compound V could, in addition to the epoxy resin, contain any components that, for example, improve the strength and / or thermal conductivity.

[0058] The mounting section 5 of the rotor shaft 2 is encased in the potting compound V in such a way that a positive connection is established between the mounting profile 6 and the rotor body 7, at least in the circumferential direction. The mounting profile 6 is thus designed so that a torque can be transmitted from the rotor module 3 to the rotor shaft 2 (motor operation) or, if applicable, a torque from the rotor shaft 2 can be transmitted to the rotor module 3 (generator operation – if possible).

[0059] The permanent magnets 4 are also encased circumferentially by the potting compound V in such a way that they are held on the rotor body 7 without any further fastening means. The permanent magnets 4 are encased by the potting compound V in such a way that the effective surfaces facing away from each other in the direction of their magnetic axes (which, in the assembled state, interact with corresponding electrical coils of a stator via an air gap in the axial flux motor) are free, i.e., not covered by the potting compound V. The effective surfaces are shown in Fig. 1a. In the example shown, the effective surfaces are essentially coplanar to the end faces of the rotor body 7, i.e., the permanent magnets 4 do not project beyond the end faces of the rotor body 7 in the axial direction.Alternatively, the permanent magnets 4 could also protrude slightly beyond the end faces, for example, if the permanent magnets 4 are arranged in positioning pockets 36 provided for this purpose during manufacturing, as will be described in more detail later with reference to Fig. 5.

[0060] In the example shown, the permanent magnets 4 are trapezoidal and have correspondingly trapezoidal effective surfaces. Alternatively, other shapes would also be conceivable, for example rectangular, especially square, or round, especially circular, with correspondingly shaped effective surfaces.

[0061] In the illustrated embodiment, the permanent magnets 4 are made in one piece (see also Fig. 5). Alternatively, however, it would also be conceivable for the permanent magnets 4 to be made in multiple parts. For example, segmented permanent magnets 4 could be used, which comprise several separate magnet segments 4a that can be assembled to form a complete permanent magnet 4. An exemplary segmented permanent magnet 4 with a rectangular effective area is shown in Fig. 5. The permanent magnet 4 has several elongated magnet segments 4a that can be joined together to form the complete permanent magnet 4.

[0062] In the illustrated embodiment, the mounting profile 6 has a toothed section, as can be seen in Fig. 1a. The teeth are encased in the potting compound V, and the spaces between the teeth are filled with the potting compound V. The toothed section extends over the entire length of the mounting section. If the mounting section 5, as shown in Fig. 1b, has a larger diameter than the rest of the rotor shaft 2, then the mounting profile 6 could also be spaced axially from opposite end faces of the mounting section 5.

[0063] Alternatively or additionally, the fastening profile 6 could also have other or further (not shown) profiles, preferably comprising at least one, and in particular several, of the following profiles: a recess, in particular a groove or bore; a projection, in particular a rib or pin. The fastening profile 6 could optionally also have an undercut, so that an improved connection between the potting compound V and the fastening section 5 is created.

[0064] In the illustrated embodiment, the rotor body 7 further comprises a reinforcing insert 10, preferably non-metallic, which is preferably completely encased in the potting compound V, as shown in Fig. 1b. The reinforcing insert 10 is preferably arranged in a plane of the rotor body 7 perpendicular to the longitudinal axis L, in particular a plane of symmetry.

[0065] The reinforcing insert 10 can, for example, comprise a mat or a mesh made of textile fibers, preferably of an aromatic polyamide. Alternatively or additionally, a mat or a mesh made of a glass fiber reinforced plastic and / or a mat or a mesh made of a carbon fiber reinforced plastic could also be provided. Fig. 1a shows a section of such a mesh.

[0066] In the illustrated example, a plurality of stiffening ribs 11 are provided on the axially opposite end faces of the rotor body 7, spaced apart from one another in the circumferential direction. Viewed radially, the stiffening ribs 11 are located in a region between the permanent magnets 4 and the mounting section 5 of the rotor shaft 2. The stiffening ribs 11 can, for example, have a substantially triangular cross-section, as can be seen in Fig. 1b. The wider section of the triangle is located radially inward.

[0067] The rotor module 3 preferably comprises a closed stabilizing ring 12 located radially outside the permanent magnets 4. Similar to the permanent magnets 4, the stabilizing ring 12 is also held on the rotor body 7, preferably exclusively, by the potting compound V. The stabilizing ring 12 is preferably encased in the potting compound V at least radially outside the rotor body. In the example shown, the stabilizing ring 12 is in particular encased on all sides, as can be seen in Fig. 1b.

[0068] The stabilizing ring 12 can be made of a metallic material, in particular aluminum, or of a non-metallic material, in particular carbon. Since the stabilizing ring 12 essentially only absorbs tensile forces, it could also be flexible, for example, in the form of a rope or a band. The stabilizing ring 12 can have several circumferentially spaced positioning projections 13 on an inner circumferential surface. In the example shown, each positioning projection 13 is located circumferentially within the region of a permanent magnet 4, in particular without contacting an outer circumferential surface of the respective permanent magnet 4.According to an alternative embodiment (not shown), the stabilizing ring 12 could also be designed and arranged such that a positioning projection 13 extends radially between two circumferentially adjacent permanent magnets 4, in particular without contacting the permanent magnets 4. The positioning projections 13 serve, in particular, to position the permanent magnets 4 during manufacturing. Details will be explained later with reference to an exemplary manufacturing process in conjunction with Figures 3 to 8.

[0069] The permanent magnets 4 can each have a retaining profile 14 on at least their circumferentially opposite outer surfaces, which is form-fittingly encased or cast in the potting compound V. Additionally, the inner circumferential surface and / or the outer circumferential surface could each also comprise a retaining profile 14. The retaining profile 14 can, for example, have an undercut and / or at least one, preferably several, of the following profiles: a recess, in particular a groove or bore; a projection, in particular a rib or pin. Two exemplary retaining profiles 14 are indicated in Fig. 5.

[0070] An exemplary axial flux motor 28 is described in more detail below with reference to Fig. 2. The axial flux motor 28 has a stator 29 with a stator housing 30, which comprises a first housing half 31 and a second housing half 32. The axial flux motor 28 also has a rotor 1 with a rotor shaft 2, which is rotatably mounted in the stator housing 30, for example by means of suitable rolling bearings 45. The rotor 1 is designed according to the invention, for example as described above.

[0071] Several electrical coils 33 are arranged on both the first housing half 31 and the second housing half 32. The coils 33 are arranged circumferentially spaced apart from one another. The rotor module 3 of the rotor 1 is located axially between the coils 33 of the first housing half 31 and the coils 33 of the second housing half 32. As already described, several circumferentially spaced permanent magnets 4 are provided on the rotor module 3, which magnetically interact with the coils 33 of the stator 29. By appropriately controlling the coils 33 using a suitable control unit (not shown), a rotating magnetic field can be generated, which acts on the permanent magnets 4 and sets the rotor 1 into rotation, as indicated by the curved arrow in Fig. 2.

[0072] The coils 33 are arranged radially such that they lie within the area of ​​the permanent magnets 4 of the rotor 1. A first end face of the rotor module 3 (left in Fig. 2) thus faces the coils 33 of the first housing half 31, and the opposite second end face of the rotor module 3 (right in Fig. 2) thus faces the coils 33 of the second housing half 32. The permanent magnets 4 are each spaced from the coils 33 by a defined, as constant and as small a clearance as possible.

[0073] The following describes in detail a method for manufacturing a rotor 1 for an axial flux motor 28 according to an exemplary embodiment of the invention with reference to Figures 3 to 8. Figure 3 shows an exemplary rotor shaft 2 on the left and a longitudinal section through a mold 15 for carrying out the method on the right. Figure 4 shows a top view of a first mold half 17 of the mold 15 including the rotor shaft 2 arranged thereon.

[0074] In a first step, the rotor shaft 2 for the rotor 1 is provided, wherein the rotor shaft 2 comprises a longitudinal axis L and two shaft ends 2a, 2b. The rotor shaft 2 further comprises a mounting section 5 located between the shaft ends 2a, 2b, on the circumferential surface of which a mounting profile 6 is provided for attaching a rotor module 3.

[0075] In a further step, the mold 15 is provided, which includes a die 16 for producing a rotor body 7 for the rotor module 3. The mold 15 has a first mold half 17 with a first die section 18 of the die 16 and a second mold half 19 with a second die section 20 of the die 16. When the two mold halves 17, 19 are assembled to form the mold 15, the first die section 18 and the second die section 20 together form the die 16 (see Fig. 6).

[0076] Optionally, at least part of the surface of the die 16, in particular the inner surface of the first mold half 17 and / or the second mold half 19, can be coated with a suitable coating. The coating can, for example, be a non-stick coating, such as one comprising polytetrafluoroethylene. This simplifies the removal of the finished rotor 1. The first mold half 17 has a first shaft recess 21 in the form of a through-hole, which connects the first die section 18 to an opposite outer surface of the first mold half 17. The second mold half 19 has a second shaft recess 22 in the form of a through-hole, which connects the second die section 20 to an opposite outer surface of the second mold half 19. For shorter shafts 2, shaft recesses could also be provided which are closed in the axial direction on one side facing away from the die.

[0077] Suitable dowel pins for correctly aligning the two mold halves 17, 19 relative to each other can be provided on the mold halves 17, 19. Furthermore, suitable fasteners for joining the two mold halves 17, 19 to each other can be provided. The fasteners and dowel pins are indicated by the dashed lines in Figures 3 to 8.

[0078] In a next step, the rotor shaft 2 is arranged on the first mold half 17 such that the fastening section 5 is located in the area of ​​the first die section 18 and the first shaft end 2a is located in the area of ​​the first shaft recess 21. In the specific embodiment, the first shaft end 2 extends through the first shaft recess 21, which is designed as a through-opening, as shown in Figs. 4 and 5. Fig. 4 shows a longitudinal section through the first mold half 17 of the mold 15 with the rotor shaft 2 attached to it, and Fig. 5 shows a top view of the first mold half 17 of the mold 15 with the rotor shaft 2 attached to it.

[0079] In a further step, several permanent magnets 4 are arranged in the region of the first die section 18 of the first mold half 17 such that the magnetic axes of the permanent magnets 4 are aligned substantially parallel to the longitudinal axis L of the rotor shaft 2. It is advantageous if the longitudinal axis L of the rotor shaft 2 is aligned substantially vertically during the positioning of the permanent magnets 4. This facilitates the arrangement of the permanent magnets 4. Thus, one magnetic pole, e.g., the north pole, points vertically upwards, and the opposite magnetic pole, e.g., the south pole, points downwards and faces the end face of the first die section 18. The downward-facing end faces of the permanent magnets 4 preferably rest against the end face of the first die section 18, as can be seen in Fig. 4.In the radial direction, the permanent magnets 4 are arranged at a defined radial distance R from the longitudinal axis L. Adjacent permanent magnets 4 are arranged at a defined circumferential distance U from each other with respect to the longitudinal axis L. The circumferential distance U and the radial distance R are determined by the design constraints of the axial flux motor 28 for which the rotor 1 is manufactured. Therefore, the circumferential distance U and the radial distance R can vary.

[0080] As shown in Fig. 5, positioning elements 26 for positioning the permanent magnets 4 can be arranged within the first mold half 17 on an end face facing the first die section 18 in the axial direction. In the example shown, each positioning element 26 is arranged in a circumferentially viewed area located between two adjacent permanent magnets 4 (or at the locations where the permanent magnets 4 are arranged – indicated by dashed lines in Fig. 5).

[0081] Viewed radially, the positioning elements 26 are arranged in a central region of the permanent magnets 4. After the permanent magnets 4 have been positioned, the positioning elements 26 project axially between the adjacent permanent magnets 4. The length of the positioning elements 26 can be, for example, in the range of 10% to 80% of the thickness of the permanent magnets 4 (viewed along the magnet axis), preferably a maximum of 100%. The positioning elements 26 serve to hold the permanent magnets 4 in position during the casting process described below.

[0082] According to a preferred embodiment of the method, the permanent magnets 4 are held in position on the first mold half 17 by means of holding magnets 25. For this purpose, the holding magnets 25 are preferably arranged on the outer surface of the first mold half 17 opposite the first die section 18 and exert a magnetic holding force on the permanent magnets 4 through the first mold half 17, as indicated by the double arrows in Fig. 4. For example, a corresponding holding magnet 25 can be provided for each permanent magnet 4.

[0083] Permanent magnets, as shown in Fig. 4, can be used as holding magnets 25. Alternatively, electromagnets could also be used. These have the advantage that the magnetic holding force can be deactivated after the casting mold 15 has been filled, thus making demolding of the rotor 1 easier. The holding magnets 25 can also be arranged, for example, on a suitable magnet holder 35, which can be attached or attachable to the outside or underside of the first mold half 17. The magnet holder 35 is indicated in Fig. 4.

[0084] If permanent magnets 25 are used as holding magnets, they can, for example, be brought into a rest position before the permanent magnets 4 are arranged, in which they are sufficiently far away axially from the first die section 18 so that no or only a negligible magnetic holding force acts on the permanent magnets 4. After the permanent magnets 4 have been correctly positioned on the first mold half 17, for example using the positioning elements 26, the holding magnets 15 can be moved from the rest position to a working position in which they are closer axially to the first die section 18, so that a higher, in particular a maximum, magnetic holding force acts on the permanent magnets 4.

[0085] Preferably, the holding force exerted by the holding magnets 25 on the permanent magnets 4 in the operating position is greater than the magnetic attraction between adjacent permanent magnets 4. This reduces the risk of permanent magnets 4 tilting and sticking together, possibly due to the attraction force. With identical magnetic properties of the holding magnets 25 and the permanent magnets 4, this can be achieved, for example, by ensuring that the axial distance between the holding magnets 25 and the permanent magnets 4 is smaller than the circumferential distance between adjacent permanent magnets 4.

[0086] Contrary to the illustration in Fig. 4, the holding magnets 25 could, for example, also be arranged in suitable recesses of the first mold half 17 and be axially displaceable therein between the rest position and the working position (indicated by dashed lines). Preferably, all holding magnets 25 can be moved together, e.g., by connecting the holding magnets 25 by means of a suitable coupling unit.

[0087] In the illustrated example, permanent magnets 4 are arranged in an even number of first magnet groups 8 and an identical number of second magnet groups 9. The first magnet groups 8 and the second magnet groups 9 alternate circumferentially and have opposite magnetic polarities. In the first magnet groups 8 and the second magnet groups 9, two permanent magnets 4 with the same polarity are provided in each. Of course, this is only an example, and it would also be possible to provide only one permanent magnet 4 per magnet group 8, 9.

[0088] As indicated in Fig. 5, the permanent magnets 4 can each have a retaining profile 14 on their circumferential outer surfaces, which is designed to be positively encased or cast by the potting compound V. Optionally, the retaining profile 14 could also have an undercut (not shown), which improves the retention of the potting compound V. In the example shown, the retaining profile 14 includes projections in the form of ribs. Alternatively, other profiles would also be conceivable, e.g., projections in the form of pins or one or more recesses, in particular grooves or bores, as indicated on the rectangular segmented permanent magnet 4 in Fig. 5.

[0089] It can be advantageous if a plurality of recesses 34 for generating stiffening ribs 11 on the finished rotor body 7 are provided on one of the end faces of the first mold half 17 facing the die 16 in the axial direction within the first die section 18. The recesses 34 are shown in Fig. 5 and indicated in Fig. 4.

[0090] The recesses 34 are spaced apart from each other in the circumferential direction and are located, viewed radially, in an area between the permanent magnets 4 and the mounting section 5 of the rotor shaft 2.

[0091] Furthermore, it can be advantageous if a closed stabilizing ring 12 is arranged radially outside the permanent magnets 4 in the first die section 18 of the first mold half 17. The stabilizing ring 12 can be encased by the potting compound V at least radially outside, preferably on all sides, so that after curing, the stabilizing ring 12 is held on the rotor body 7, preferably exclusively, by the potting compound V.

[0092] The stabilizing ring 12 can, for example, be a substantially dimensionally stable ring made of a metallic material, in particular comprising aluminum, or of a non-metallic material, in particular comprising carbon. Alternatively, a flexible ring, in particular a rope or band, could also be used as the stabilizing ring 12. In the example shown, the stabilizing ring 12 comprises several circumferentially spaced positioning projections 13 on an inner circumferential surface. The stabilizing ring 12 is arranged here such that each positioning projection 13 lies in the region of a permanent magnet 4 when viewed circumferentially, preferably without contacting an outer circumferential surface of the respective permanent magnet 4.

[0093] Alternatively, the stabilizing ring could also be arranged such that a positioning projection 13 extends radially between two circumferentially adjacent permanent magnets 4, preferably without contacting the permanent magnets 4 (not shown). The positioning projections 13, particularly in combination with the positioning elements 26, reduce, and in particular prevent, the risk of unwanted displacement of the permanent magnets 4.

[0094] Alternatively or additionally to the positioning projections 13 and the positioning elements 26, positioning pockets 36 could also be provided on the end face of the first mold half 17 facing the die 16, for a number of permanent magnets 4, preferably for each permanent magnet 4. The positioning pockets 36 are indicated by dashed lines in Fig. 5. One shape of the positioning pocket 36 preferably corresponds to a shape or

[0095] Outer contour of the permanent magnet 4. The permanent magnet 4 can thus be arranged in a form-fitting manner within the positioning pocket 36 and is therefore protected against unwanted displacement.

[0096] Contrary to the illustration, however, it would also be possible, for example, to provide only a single annular positioning pocket 36 in which all permanent magnets 4 can be arranged. The permanent magnets 4 could thereby be positioned in a substantially form-fit manner in the radial direction. In the circumferential direction, the permanent magnets 4 could, for example, be freely movable. Preferably, however, positioning elements 26 are also provided here to prevent an undesired displacement of the permanent magnets 4 in the circumferential direction.

[0097] If one or more positioning pockets 36 are provided, the permanent magnets 4 in the finished rotor 1 would project beyond the end faces of the rotor body 7 by the depth of the positioning pockets 36 (not shown). Furthermore, it can be advantageous to insert a reinforcing insert 10, preferably non-metallic, in the first die section 18. The reinforcing insert 10 can later be encased, preferably on all sides, by the casting compound V. The reinforcing insert 10 preferably lies in a plane perpendicular to the longitudinal axis L of the rotor body 7 to be produced, in particular a plane of symmetry. This plane can, for example, be a parting line of the mold 15.As reinforcement insert 10, preferably a mat or a net made of textile fibers, in particular of an aromatic polyamide, and / or a mat or a net made of a glass fiber reinforced plastic and / or a mat or a net made of a carbon fiber reinforced plastic is used.

[0098] Suitable spacers 37 can be provided to correctly position the stabilizing ring 12 and / or the reinforcing insert 10. These spacers hold the stabilizing ring 12 or the reinforcing insert 10 in the desired axial position so that they can be completely encased. Exemplary spacers 37 for the reinforcing insert 10 are shown in Figures 4 and 5.

[0099] After the permanent magnets 4 and any other components (stabilizing ring 12 and / or reinforcing insert 10) have been correctly positioned, the second mold half 19 is arranged on the first mold half 17 in such a way that the second shaft end 2b is located within the second shaft recess 22. In this specific example, the second shaft end 3b extends through the second shaft recess 22, which is designed as a through-opening, as shown in Fig. 6.

[0100] The first die section 18 and the second die section 20 together form the die 16. The die 16 is thus essentially hermetically sealed. Suitable sealing materials may be provided between the two mold halves 17, 19 (not shown). For example, a suitable liquid gasket, a flat gasket, or possibly a sealing cord arranged in a groove circumferentially around the die 16 could be used as a sealing material.

[0101] In a further step, the die 16 is filled with a casting compound V, as shown in Fig. 7. The casting compound V is introduced into the die 16 in its liquid state through a number of filling openings 23 provided on the mold 15. This introduction can be done manually by a person or, if necessary, automatically using a suitable filling device (not shown). Fig. 7 shows only two filling openings 23 by way of example, which are arranged on the second mold half 19. The filling openings 23 each connect the surroundings to the second die section 20. Of course, more or fewer filling openings 23 can be provided. Filling openings 23 can also be provided on the first mold half 17. The casting compound V is shown here in the form of tube-shaped containers B. This is, of course, only an example, and suitable containers B can be used.For example, the containers B with the potting compound V can also be pressurized to improve the application.

[0102] Optionally, a vacuum can be created in the die 16 before and / or during casting. For this purpose, one or more suitable suction ports 27 can be provided on the mold 15. In the example shown in Fig. 7, two suction ports 27 are shown by way of example. The suction ports 27 can be connected to a vacuum pump 24, which generates the vacuum. This enables a substantially complete and as uniform a distribution as possible of the casting compound V in the die 16. In addition, the risk of air inclusions forming, which can negatively affect the strength and mass distribution of the rotor 1, is reduced.

[0103] The suction ports 27 can optionally also function as overflow channels for the potting compound V. Alternatively, separate overflow channels (not shown) could be provided. If the volume of the die 16 is known, the amount of potting compound V to be introduced can be determined as a function of the volume and introduced, for example, automatically or manually. A suitable sensor or a viewing window could also be provided to detect whether potting compound V is present in the overflow channels or is leaking from them. The filling process can be stopped upon detection.

[0104] After the filling process is complete, the potting compound V is cured in a further step. In the simplest case, the mold 15 can remain closed for a certain period of time. Optionally, a heating device 38 (indicated in Fig. 7) could be provided to heat the mold 15 and thereby accelerate the curing process. The heating device 38 could, for example, include flow channels integrated into one or both mold halves 17, 19, through which a temperature-controlled liquid can flow. Alternatively, the heating device 38 could also include an electric heater, in particular a resistance heater, as shown by way of example in Fig. 7.

[0105] Optionally, the mold 15 could be moved, shaken, and / or rotated during and / or after pouring, preferably by means of a (not shown) motion device. This can reduce or prevent the formation of air inclusions.

[0106] Additionally or alternatively, it can be advantageous to reduce the viscosity of the potting compound V before or during pouring by tempering the potting compound V to a predetermined temperature. This can be achieved, for example, by means of a suitable tempering device 39, which is shown by way of example in Fig. 7. The tempering device 39 can, for example, include a suitable hot air blower. The specific design of the tempering device 39 can, of course, vary and depends essentially on the form in which the potting compound V is provided. If necessary, the potting compound V could also be stored in a heated container and warmed before pouring.

[0107] After the potting compound V has hardened, the second mold half 19 is separated from the first mold half 17 in a further step, as shown in Fig. 8. Finally, the finished rotor 1 can be removed from the mold 15. The rotor 1 is generally ready for use. However, minor finishing work may still be necessary, such as removing excess potting compound V from the transfer channels. Balancing the rotor 1 may also be necessary if the weight distribution is uneven, for example, due to recesses created by the positioning elements 26 or spacers 37.

[0108] In another aspect, the invention relates to a spindle drive 40, as described in more detail below with reference to Fig. 9. Fig. 9 shows a longitudinal section through the spindle drive 40.

[0109] The spindle drive 40 comprises, in a known manner, a threaded spindle 41 and a spindle nut 42 rotatably arranged on the threaded spindle 41. The spindle drive 40 also includes a suitable drive unit 43, which is configured to rotate the spindle nut 42 in order to move the threaded spindle 41 axially relative to the spindle nut 42, as indicated by the double arrow. The drive unit 43 is designed as an axial flux motor according to the invention. The axial flux motor 28 can be configured as described above with reference to Figures 1 to 8. The spindle drive 40 enables the conversion of a rotary motion of the axial flux motor 28 into a linear motion of the threaded spindle 41.

[0110] In the illustrated example, the rotor shaft 2 of the axial flux motor 28 is designed as a hollow shaft. The hollow shaft also forms the spindle nut 42. The hollow shaft is rotatably mounted in the stator housing 30. Viewed in the axial direction (in the direction of the axis of rotation or longitudinal axis of the threaded spindle 41), the hollow shaft 42 is fixed relative to the stator housing 30. Alternatively, the spindle nut 42 could also be designed as a separate component, and the hollow shaft could be connected to the spindle nut in a rotationally fixed and, if necessary, detachable manner. The threaded spindle 41 extends through the hollow shaft and can, for example, serve to exert a force F, as indicated by the arrow in Fig. 9.

[0111] Advantageously, several rolling elements 44 can be provided between the threaded spindle 41 and the spindle nut 42. In the illustrated embodiment, the rolling elements 44 are merely examples of balls, and the threaded spindle 41 is designed as a ball screw. Depending on the application, however, other designs can also be used, for example, the planetary roller screw drive mentioned at the beginning. In simpler embodiments, rolling elements 44 could also be omitted, and, for example, a trapezoidal thread or flat thread could be provided.

[0112] In the illustrated embodiment, the rotor shaft 2 or hollow shaft is supported in the stator housing 30 by means of four rolling bearings 45. For example, the two inner rolling bearings 45 can be designed as radial bearings, which primarily serve to absorb the radially acting forces and can only absorb comparatively small axial forces. Ball bearings, in particular radial ball bearings, or roller bearings, in particular cylindrical roller bearings, can be provided as radial bearings. The use of needle roller bearings would also be conceivable in order to reduce the radial dimensions. When using needle roller bearings, a separate inner ring could potentially be omitted, and the rotor shaft 2 or hollow shaft could assume the function of the inner ring.

[0113] The two outer rolling bearings 45 can, for example, be designed as thrust bearings, which primarily absorb axial forces and can only absorb comparatively small radial forces. Radial forces are mainly generated during operation by the axial flux motor 28. Axial forces, e.g., the force F shown in Fig. 9, can be generated during operation of the spindle drive 40 via the threaded spindle 41 or act on the threaded spindle 41 in the form of reaction forces. Ball bearings, in particular thrust ball bearings, or roller bearings, in particular cylindrical roller bearings, can again be provided as thrust bearings.

[0114] Contrary to the illustration, it would also be sufficient in principle if only two rolling bearings 45 were provided, which are designed to absorb both radial and axial forces. Examples of such rolling bearings 45 are angular contact ball bearings, tapered roller bearings, etc. Of course, other types of bearing arrangements could also be provided instead of rolling bearings 45, e.g., magnetic bearings or plain bearings.

[0115] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0116] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0117] All references to value ranges in this description are to be understood as encompassing any and all sub-ranges thereof. For example, the reference 1 to 10 is to be understood as including all sub-ranges, starting with a lower limit of 1 and ending with an upper limit of 10. This means that all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10. Finally, for the sake of clarity, it should be noted that, for better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced.

[0118] Reference numeral list

[0119] 1 Rotor 26 Positioning element

[0120] 2 Rotor shaft 27 Suction port

[0121] 2a first shaft end 28 axial flux motor

[0122] 2b second shaft end 29 stator

[0123] 3 Rotor module 30 Stator housing

[0124] 4 Permanent magnet 31 First housing half

[0125] 4a Magnet segment 32 second housing half

[0126] 5 B fastening s from section 33 electrical coils

[0127] 6 B fastening profile 34 recesses

[0128] 7 rotor bodies 35 magnet holders

[0129] 8 first magnet group 36 positioning pocket

[0130] 9 second magnet group 37 spacers

[0131] 10 Reinforcement insert 38 Heating device

[0132] 11 Stiffening rib 39 Temperature control device

[0133] 12 S stabilization sring 40 spindle drive

[0134] 13 Positioning advantage 41 Threaded spindle

[0135] 14 Retaining profile 42 Spindle nut

[0136] 15 Mold 43 Drive unit

[0137] 16 dies, 44 rolling elements

[0138] 17 first mold half 45 rolling bearings

[0139] 18 first matrix section V casting compound

[0140] 19 second half of mold L longitudinal axis

[0141] 20 second matrix section U circumference from stand

[0142] 21 first wave recess R radial spacing

[0143] 22 second wave recess B container

[0144] 23 Filling opening

[0145] 24 Vacuum pump

[0146] 25 Holding magnet

[0147] Patent claims

Claims

P a t e n t a n s p r ü c h e 1. Rotor (1) for an axial flux motor (28), comprising a rotor shaft (2) with a longitudinal axis (L) and a rotor module (3) attached to the rotor shaft (2), wherein the rotor module (3) comprises several permanent magnets (4) spaced apart from one another in the circumferential direction with respect to the longitudinal axis (L), wherein the magnet axes of the permanent magnets (4) are arranged substantially parallel to the longitudinal axis (L), characterized in that the rotor shaft (2) has a mounting section (5) on the circumferential surface of which a mounting profile (6) is provided, and that the rotor module (3) comprises a rotor body (7) made of a potting compound (V), preferably comprising an epoxy resin, wherein the mounting section (5) of the rotor shaft (2) is encased in the potting compound (V) in such a manner thatthat a positive connection is established between the mounting profile (6) and the rotor body (7) at least in the circumferential direction, and that the permanent magnets (4) are encased circumferentially by the potting compound (V) in such a way that they are held on the rotor body (7), in particular without further fastening means.

2. Rotor (1) according to claim 1, characterized in that the permanent magnets (4) comprise an even number of first magnet groups (8) and an identical number of second magnet groups (9), wherein the first magnet groups (8) and the second magnet groups (9) alternate in the circumferential direction and have opposite poles, wherein the first magnet groups (8) each comprise at least one permanent magnet (4) and the second magnet group (9) each comprise at least one permanent magnet (4).

3. Rotor (1) according to claim 1 or 2, characterized in that the fastening profile (6) comprises a toothing and / or at least one, preferably several, of the following profiles: recess, in particular groove or bore; projection, in particular rib or pin and / or that the fastening profile (6) has an undercut.

4. Rotor (1) according to one of claims 1 to 3, characterized in that the fastening section (5) has a larger diameter than the rest of the rotor shaft (2) and the fastening profile (6) is spaced axially from opposite end faces of the fastening section (5).

5. Rotor (1) according to one of claims 1 to 4, characterized in that the rotor body (7) consists at least 90%, preferably at least 95%, in particular substantially entirely of the potting compound (V).

6. Rotor (1) according to one of claims 1 to 5, characterized in that the rotor body (7) comprises a, preferably non-metallic, reinforcing insert (10) which is preferably completely surrounded by the potting compound (V), wherein the reinforcing insert (10) is preferably located in a plane normal to the longitudinal axis (L) of the rotor body (7), in particular a plane of symmetry.

7. Rotor (1) according to claim 6, characterized in that the reinforcement insert (10) comprises a mat or a net made of textile fibers, preferably made of an aromatic polyamide, and / or a mat or a net made of a glass fiber reinforced plastic and / or a mat or a net made of a carbon fiber reinforced plastic.

8. Rotor (1) according to one of claims 1 to 7, characterized in that the rotor body (7) comprises at least on one end face, preferably on both end faces, a plurality of stiffening ribs (11) which are spaced apart from each other in the circumferential direction and which, viewed in the radial direction, are located in an area between the permanent magnets (4) and the mounting section (5) of the rotor shaft (2).

9. Rotor (1) according to one of claims 1 to 8, characterized in that the rotor module (3) comprises a closed stabilizing ring (12) located radially outside the permanent magnets (4), wherein the stabilizing ring (12) is held on the rotor body (7), preferably exclusively, by the potting compound (V), wherein the stabilizing ring (12) is preferably encased at least radially outside, in particular on all sides, by the potting compound (V).

10. Rotor (1) according to claim 9, characterized in that the stabilizing ring (12) is made of a metallic material, in particular comprising aluminium, or of a non-metallic material, in particular comprising carbon and / or that the stabilizing ring (12) is flexible.

11. Rotor (1) according to claim 9 or 10, characterized in that the stabilizing ring (12) comprises several positioning projections (13) spaced apart from each other in the circumferential direction on an inner circumferential surface, wherein each positioning projection (13) projects radially between two circumferentially adjacent permanent magnets (4), in particular without contacting the permanent magnets (4), or each positioning projection (13) is arranged in the circumferential direction in the region of a permanent magnet (4), in particular without contacting an outer circumferential surface of the respective permanent magnet (4).

12. Rotor (1) according to one of claims 1 to 11, characterized in that the permanent magnets (4) each have a retaining profile (14) at least on their circumferentially opposite outer sides, which is positively encased or cast by the potting compound (V).

13. Rotor (1) according to claim 12, characterized in that the retaining profile (14) has an undercut and / or that the retaining profile (14) comprises at least one, preferably several, of the following profiles: recess, in particular groove or bore; projection, in particular rib or pin.

14. Axial flux motor (28) comprising a stator (29) with a stator housing (30) having a first housing half (31) and a second housing half (32), and comprising a rotor (1) with a rotor shaft (2) rotatably mounted in the stator housing (30), wherein several electrical coils (33) are arranged on each of the first housing half (31) and the second housing half (32), and wherein several circumferentially spaced permanent magnets (4) are provided on a rotor module (3) of the rotor (1) located axially between the first housing half (31) and the second housing half (32), which magnetically interact with the coils (33) of the stator (29) to generate the to set the rotor (1) in rotation, characterized in that the rotor (1) is designed according to one of claims 1 to 13.

15. Spindle drive (40) comprising a threaded spindle (41), a spindle nut (42) rotatably arranged on the threaded spindle (41) and a drive device (43) configured to rotate the spindle nut (42) in order to move the threaded spindle (41) in an axial direction relative to the spindle nut (42), characterized in that the drive device (43) is configured as an axial flux motor (28) according to claim 14.

16. Spindle drive (40) according to claim 15, characterized in that several rolling elements (44) are provided between the threaded spindle (41) and the spindle nut (42).

17. Spindle drive (40) according to claim 15 or 16, characterized in that the rotor shaft (2) of the axial flux motor (28) is designed as a hollow shaft and either forms the spindle nut (42) or is connected to the spindle nut (42), in particular in a rotationally fixed manner, and that the threaded spindle (41) extends through the hollow shaft.

18. Method for manufacturing a rotor (1) for an axial flux motor (28) comprising the following steps: - Providing a rotor shaft (2) with a longitudinal axis (L) and two shaft ends (2a, 2b), wherein the rotor shaft (2) comprises a mounting section (5) located between the shaft ends (2a, 2b), on the circumferential surface of which a mounting profile (6) is provided for attaching a rotor module (3), - Providing a mold (15) comprising a die (16) for producing a rotor body (7) for the rotor module (3), wherein the mold (15) comprises a first mold half (17) with a first die section (18) of the die (16) and a second mold half (19) with a second die section (20) of the die (16), wherein the first mold half (17) comprises a first shaft recess (21) and the second mold half (19) comprises a second shaft recess (22). - Arrange the rotor shaft (2) on the first mold half (17) such that the fastening s section (5) is located in the area of ​​the first die section (18) and the first wave end (2a) is located in the first wave recess (21), - Positioning several permanent magnets (4) in the area of ​​the first matrix section (18) of the first mold half (17) such that the magnet axes of the permanent magnets (4) are oriented substantially parallel to the longitudinal axis (L) of the rotor shaft (2), the permanent magnets (4) are spaced apart in the radial direction at a defined radial distance (R) from the longitudinal axis (L), and adjacent permanent magnets (4) are spaced apart in the circumferential direction with respect to the longitudinal axis (L) at a defined circumferential distance (U). - Arranging the second mold half (19) on the first mold half (17) such that the second wave end (2b) is located in the second wave recess (22) and the two matrix sections (18, 20) together form the one substantially hermetically sealed matrix (16), - Pouring the die (16) with a casting compound (V) by introducing the casting compound (V) in liquid form into the die (16) through a number of filling openings (23) of the mold (15), - Curing of the potting compound (V), - Detaching the second mold half (19) from the first mold half (17), - Removing the rotor (1) from the mold (15).

19. Method according to claim 18, characterized in that the first wave recess (21) of the first mold half (17) is designed as a through opening which connects the first die section (18) with an opposite outer surface, wherein the first wave end (2a) extends through the through opening and / or that the second wave recess (22) of the second mold half (19) is designed as a through opening which connects the second die section (20) with an opposite outer surface, wherein the second wave end (2b) extends through the through opening.

20. Method according to claim 18 or 19, characterized in that the permanent magnets (4) are arranged in an even number of first magnet groups (8) and an identical number of second magnet groups (9), wherein the first magnet groups (8) and the second magnet groups (9) are arranged alternately and with opposite polarity in the circumferential direction, wherein at least one permanent magnet (4) is provided in each of the first magnet groups (8) and the second magnet groups (9).

21. Method according to one of claims 18 to 20, characterized in that a vacuum is generated in the die (16) before and / or during the casting of the die (16), in particular by means of a vacuum pump (24).

22. Method according to one of claims 18 to 21, characterized in that the longitudinal axis (L) of the rotor shaft (2) is oriented substantially vertically at least during the positioning of the permanent magnets (4).

23. Method according to one of claims 18 to 22, characterized in that the permanent magnets (4) are held in position on the first mold half (17) by means of holding magnets (25), wherein the holding magnets (25) are arranged on the outer side of the first mold half (17) opposite the first matrix section (18) and exert a magnetic holding force on the permanent magnets (4) through the first mold half (17), wherein electromagnets or permanent magnets are used as holding magnets (25).

24. Method according to one of claims 18 to 23, characterized in that positioning elements (26) are arranged on an end face of the first mold half (17) facing the first die section (18) in the axial direction, wherein each positioning element (26) is located in a circumferential direction in an area between two adjacent permanent magnets (4) and projects in an axial direction between the adjacent permanent magnets (4) in order to hold the permanent magnets (4) in position during casting, wherein the positioning elements (26) are preferably arranged in a central area of ​​the permanent magnets (4) in a radial direction.

25. Method according to one of claims 18 to 24, characterized in that a closed stabilizing ring (12) is arranged radially outside the permanent magnets (4) in the first die section (18) of the first mold half (17), which is encased at least radially outside, preferably on all sides, by the potting compound (V), so that the stabilizing ring (12) is held on the rotor body (7) after hardening, preferably exclusively, by the potting compound (V).

26. Method according to claim 25, characterized in that a ring made of a metallic material, in particular comprising aluminium, or of a non-metallic material, in particular comprising carbon, is used as the stabilizing ring (12) and / or that a flexible ring, in particular a rope, is used as the stabilizing ring (12).

27. Method according to claim 25 or 26, characterized in that the stabilizing ring (12) comprises several circumferentially spaced positioning projections (13) on an inner circumferential surface, wherein the stabilizing ring (12) is arranged such that a positioning projection (13) projects radially between two circumferentially adjacent permanent magnets (4), preferably without contacting the permanent magnets (4), or wherein a positioning projection (13) is arranged circumferentially in the region of a permanent magnet (4), preferably without contacting an outer circumferential surface of the respective permanent magnet (4).

28. Method according to one of claims 18 to 27, characterized in that the permanent magnets (4) each have a retaining profile (14) at least on their circumferentially opposite outer sides, which is positively encased or cast by the potting compound (V), wherein the retaining profile (14) preferably has an undercut and / or comprises at least one, preferably several, of the following profiles: recess, in particular groove or bore; projection, in particular rib or pin.

29. Method according to one of claims 18 to 28, characterized in that a, preferably non-metallic, reinforcing insert (10) is inserted in the first matrix section (18), which is preferably completely surrounded by the potting compound (V), wherein the reinforcing insert (10) is preferably located in a plane normal to the longitudinal axis (L) of the rotor body (7), in particular a plane of symmetry, and wherein the reinforcing insert (10) is preferably a mat or a mesh made of textile fibers, in particular of an aromatic polyamide, and / or a mat or a mesh made of a glass fiber reinforced plastic and / or a mat or a mesh made of a carbon fiber reinforced plastic.

30. Method according to one of claims 18 to 29, characterized in that a plurality of recesses (34) for generating stiffening ribs (11) on the finished rotor body (7) are provided on an end face of the first mold half facing the die (16) in the axial direction, which are spaced apart from each other in the circumferential direction and which are located in a radial direction in an area between the permanent magnets (4) and the fastening section (5) of the rotor shaft (2).

31. Method according to one of claims 18 to 30, characterized in that the mold (15) is moved and / or shaken and / or rotated during and / or after pouring.

32. Method according to one of claims 18 to 31, characterized in that the viscosity of the potting compound (V) is reduced before or during casting by tempering the potting compound (V), preferably by means of a tempering device (39), to a predetermined temperature.

33. Method according to one of claims 18 to 32, characterized in that the mold (15) is heated at least section by means of a heating device (38) before, during or after pouring.

Images