Spoke rotor with overmolding

Abstract

Spoked rotor (10) for an electric machine, comprising a pole ring (1) and a shaft (3) arranged in the pole ring (1), the shafts extending concentrically around an axis (30) and spaced apart from one another, the pole ring (1) having a plurality of sectors (11.i) between which permanent magnets (2.i) are arranged, and a fastening element (4) formed from a first hardened mass is provided between the shaft (3) and the pole ring (1), wherein • the fastening means (4) is at least partially spoke-shaped, the spokes (41) extending in a radial direction (32), or substantially in the radial direction (32), to the axis (30); and / or • the pole ring (1) is fully surrounded by the fastening element (4), • characterized in that the spoke rotor (10) has end faces (111, 112) at axially opposite ends (101, 102) in the direction (31), wherein the fastening means extends substantially over the entire surface along the end faces (111, 112).

Description

State of the art

[0001] The present invention relates to a spoke rotor for an electrical machine with a pole ring and a shaft, between which a fastening means made of a hardened mass is arranged, the electrical machine with the spoke rotor, as well as an adjustment drive and a hand-held power tool with such an electrical machine.

[0002] Common permanent-magnet electric machines often have a spoked rotor with permanent magnets to generate the magnetic field. The permanent magnets are usually cuboid-shaped, extend longitudinally along the rotor, and are magnetized in the tangential direction.

[0003] A well-known problem with such spoked rotors is the positioning and fastening of the permanent magnets. Due to manufacturing tolerances and the ability to fit the permanent magnets into their housings, the dimensions of the housings must be larger than the outer dimensions of the permanent magnets. The difference is typically several tenths of a millimeter, often around 0.2 mm. To ensure that the permanent magnets can withstand vibrations or other mechanical stresses throughout the service life of the electric machine, such as those that occur during changes in direction during operation, the permanent magnets must be permanently fixed in their position.

[0004] A variety of methods are known for securing permanent magnets. For example, the permanent magnets are glued into their holders, or spring elements are used that push the permanent magnets either radially outward or radially inward.

[0005] It is also known to secure the permanent magnets in their holders by injecting or casting a thermoplastic, a duromer, or another plastic. The advantage of this method is that the permanent magnets can be inserted into their recesses with virtually no force.

[0006] The publication DE 10 2010 061 778 A1 discloses a spoked rotor for an electrical machine, in which a connecting sleeve is provided between the rotor shaft and the base body of the rotor, in which the permanent magnets are arranged. The connecting sleeve is made of a diamagnetic material and / or a paramagnetic material with a permeability number of less than 20, in particular of aluminum or a plastic. It can be joined as a prefabricated sleeve between the base body and the rotor shaft, or it can be formed from a hardenable mass and injected or cast between the rotor shaft and the base body. The connecting sleeve conducts the magnetic field in the spoked rotor only moderately or even displaces it, so that (almost) no stray fluxes arise on the side of the base body facing the shaft.

[0007] However, the hardenable compound shrinks during curing. In a spoked rotor where the connecting sleeve is formed from a hardenable compound and injected or cast between the base body and the rotor shaft, it has been shown that the concentricity and stability of the spoked rotor deteriorate with increasing distance between the base body and the rotor shaft.

[0008] Further prior art can be found in US 2014 / 0 103 771 A1. Disclosure of the invention

[0009] The object of the present invention is to improve such a spoked rotor so that it exhibits excellent concentricity and stability even with a large distance between the base body and the rotor shaft. A further object of the invention is to further improve the power density and efficiency of the spoked rotor, while still allowing the spoked rotor to be manufactured cost-effectively.

[0010] The object is achieved with a spoke rotor according to independent claim 1, an electric machine according to independent claim 14 and an adjustment drive according to independent claim 15. Advantageous embodiments can be found in the dependent claims.

[0011] For this purpose, a spoked rotor for an electric machine is provided, comprising a pole ring and a shaft arranged in the pole ring, which extend concentrically around an axis and are spaced apart from each other. The pole ring has a plurality of sectors between which permanent magnets are arranged. A fastening means formed from a first cured mass is provided between the shaft and the pole ring.

[0012] The spoke rotor is characterized in that the fastening means is at least partially designed in the manner of a spoke, wherein the spokes extend in a radial direction or substantially in the radial direction to the axis, and / or in that the pole ring is completely surrounded by the fastening means.

[0013] It has been shown that the spoke-like structure of the fastening element and / or the complete overmolding of the pole ring not only ensures excellent concentricity of the spoked rotor, but also sufficient stability of the spoked rotor, even at high speeds. Due to the simple structure of the sectors, the tolerance chain during production of the spoked rotor is very small. Noise generation during operation of the rotor is therefore very low. In addition, such a spoked rotor allows for a very small air gap between the spoked rotor and the stator of the electric motor. With the pole ring fully encased, the fastening element also ensures corrosion protection for the permanent magnets and the pole ring.

[0014] The sectors are intended to conduct the magnetic flux and are preferably made of a ferromagnetic material, in particular a rotor lamination. They are preferably manufactured as a lamination pack consisting of a plurality of laminations connected to one another in the axial direction, in particular by stamped stacking. Due to their very simple shape, the sectors can be manufactured cost-effectively as stamped parts with very little waste. However, manufacturing the sectors from a solid body is also preferred. In this embodiment, their very simple shape also allows for cost-effective production.

[0015] Conventional, particularly cuboid-shaped, permanent magnets are preferably used. In addition to such cuboid-shaped permanent magnets, the use of permanent magnets with other cross-sections is also preferred.

[0016] The first cured compound for the fastening means is preferably non-magnetically conductive or virtually non-magnetically conductive to prevent stray losses on the shaft-facing side of the pole ring. It is preferably formed from a plastic, a plastic-bonded, particularly diamagnetic, metal, or a metal, particularly diamagnetic. A thermoset is preferred for the plastic. Aluminum or an aluminum alloy is preferred as the metal or plastic-bonded metal. However, the use of other plastics, such as dimensionally stable thermoplastics, is also preferred.

[0017] The fastener is designed to secure and position the permanent magnets in the pole ring, to position the pole ring concentrically around the shaft, and to connect the pole ring to the shaft. It ensures torque transmission from the shaft to the pole ring.

[0018] To ensure the secure attachment and positioning of the permanent magnets in the pole ring, it is preferred that the fastening means extend over the entire surface of the inner side of the pole ring facing the shaft. The fastening means is therefore preferably annular on the inner side of the pole ring. In the following, the annular region of the fastening means arranged on the inner side of the pole ring is referred to as the outer ring of the fastening means.

[0019] Furthermore, the first cured mass is preferably elastic or elastic-plastic, so that the permanent magnets are sufficiently secured even under vibration loads during rotor operation. Due to its elasticity and / or plasticity, the fastening means is deformable against a restoring force, so that it exhibits a spring behavior and / or mechanical clamping behavior. This clamps the permanent magnet in its holder during operation of the electric machine. Furthermore, component tolerances and the temperature behavior of the permanent magnet are compensated across the range of temperatures encountered.

[0020] In the following, a material is referred to as elastic or elastic-plastic if it either behaves elastically and is therefore reversibly deformable, or if it behaves elastically and plastically and therefore still has sufficient elasticity after plastic deformation to ensure the required spring behavior and / or mechanical clamping behavior for bracing the permanent magnet during operation of the electrical machine.

[0021] The spokes of the fastening means are preferably evenly distributed in the circumferential direction. In a preferred embodiment, they extend in the radial direction. However, it is particularly preferred that they be arranged slightly obliquely relative to the radial direction. In this embodiment, they have an acute angle to the radial direction, for example, an angle of approximately 1-20°. The angle is application-specific and depends, for example, on the motor size. As a result, the sectors are drawn to the shaft at approximately this angle. This reduces the air gap between the sectors and the adjacent permanent magnets, which leads to reduced flux losses.

[0022] To secure the pole ring to the shaft, it is preferred that positive locking means be provided on the sectors. The positive locking means are designed to accommodate the first hardenable compound. They are preferably designed as recesses or grooves. They preferably have a dovetail shape. Depending on the application, it is particularly preferred that they be asymmetrical. This also leads to a reduction in the air gap between the sectors and the adjacent permanent magnets, and thus to reduced flux losses.

[0023] To secure the shaft, it is preferred that the shaft has second positive-locking means, in particular knurling. Preferably, the shaft is also completely surrounded by the fastening means. Therefore, it is further preferred that the fastening means be annular on the outer side of the shaft facing the pole ring. Hereinafter, the annular region of the fastening means arranged on the outer side of the shaft is referred to as the inner ring of the fastening means.

[0024] The spokes preferably extend between the inner ring of the fastening means and the outer ring of the fastening means. Receptacles are preferably arranged between the spokes.

[0025] In a first preferred embodiment, the receptacles are empty. In this embodiment, the spoked rotor is very lightweight. It therefore exhibits very good dynamic properties and consumes little energy. Firstly, the heat losses of the electric motor are therefore very low. Secondly, the low energy consumption allows for a reduction in the length of the rotor or electric motor in the axial direction. An electric motor with a shorter axial length is more cost-effective to manufacture.

[0026] In a second preferred embodiment, a second cured mass is arranged in the receptacles. In this embodiment, it is preferred that the second cured mass has a lower weight than the first cured mass and / or that it expands during curing. Due to the expansion during curing, the permanent magnets are pressed into their pockets arranged between the sectors. Furthermore, vibrations and oscillations can be reduced depending on the damping capacity of the selected cured mass.

[0027] However, the use of the first cured mass is also preferred as the second cured mass, wherein the second cured mass is introduced, in particular filled, into the receptacle after the first cured mass has cured.

[0028] It is further preferred that the spoke rotor has end faces at opposite ends in the axial direction, wherein the fastening means extends substantially over the entire surface of the end faces. The end faces limit displacement of the permanent magnets in the axial direction.

[0029] To simplify removal of the spoked rotor from an injection molding tool, it is also preferred that the shaft has a shoulder. The shaft has a larger diameter in the area of ​​the shoulder. The fastening means is preferably arranged either flush with the shoulder or extends axially beyond the shoulder.

[0030] To ensure that the permanent magnets are always arranged on the same side of their adjacent sectors, it is preferable that a gap filler is arranged on a first side of each permanent magnet between the permanent magnet and the sector adjacent to that side. This reduces the torque ripple of the spoke rotor. Furthermore, the gap filler compensates for manufacturing tolerances of the sectors and the permanent magnets in the overmolding tool, and its elastic or elastic-plastic behavior enables their precise positioning and overmolding.

[0031] On a second side opposite the first side of each permanent magnet, an elastic or elastic-plastic filler, in particular a thin plastic or rubber layer, is preferably provided. The filler is preferably glued or injection-molded. It particularly preferably hardens at high temperatures.

[0032] A sleeve is preferably arranged on an outer side of the overmolded or non-overmolded pole ring, facing away from the shaft. The sleeve stabilizes the spoked rotor, in particular the pole ring, against centrifugal forces at very high speeds. It is preferably made of a plastic, a fiber-reinforced plastic, or a metal, in particular aluminum. It is particularly preferably designed as a plastic film, in particular a shrink-on plastic film. However, it can also be overmolded onto the pole ring.

[0033] In a fully overmolded pole ring, the fastening means is annular on an outer side of the pole ring facing away from the shaft. In this embodiment, the annular region of the fastening means arranged on the outer side of the pole ring is referred to below as the outer shell of the fastening means. It is preferred that the outer side of the fully overmolded pole ring facing away from the shaft, i.e., the outer shell of the pole ring, is either round or corrugated. The round outer shell ensures greater mechanical strength. In comparison, the corrugated outer shell ensures better protection against magnetic losses due to heat.

[0034] The problem is still solved using an electric machine with such a spoked rotor. An electric machine is, for example, an electric motor, a generator, or a starter.

[0035] The object is also achieved with an electric motor, in particular an EC or DC motor, with such a spoked rotor. In a preferred embodiment, the electric motor is a synchronous motor, a reluctance motor, a permanent magnet DC motor, an external rotor motor, or an electric motor with a different topology. In a particularly preferred embodiment, the electric motor is an EC internal rotor motor.

[0036] The problem is further solved by an adjustment drive, in particular for a motor vehicle, comprising an electric motor with such a spoked rotor. Such an adjustment drive is, for example, a tailgate drive, a window lift drive, a servo drive, a wiper, a fan, or a seat adjustment drive. Furthermore, the problem is solved by a handheld power tool with an electric motor comprising such a spoked rotor. Such a handheld power tool is, for example, a drill, a jigsaw, or electric scissors.

[0037] The invention is described below with reference to figures. These figures are merely exemplary and do not limit the general concept of the invention. Fig. 1 shows in (a) - (c) each a pole ring of a spoke rotor according to the invention; Fig. 2 shows in (a) and (b) an arrangement of a permanent magnet, a sector and a gap filler of a pole ring of a spoke rotor according to the invention, and in (c) a positive locking means of a sector of a pole ring of a spoke rotor according to the invention; Fig. 3 shows in (a) a perspective view of a first embodiment of a spoke rotor according to the invention, in (b) a section through the spoke rotor from (a) transverse to the axis, and in (c) a section through the spoke rotor from (a) in the axial direction; Fig. 4 shows in (a) a perspective view of a further embodiment of a spoke rotor according to the invention, in (b) a section through the spoke rotor from (a) transverse to the axis, and in (c) a section through the spoke rotor from (a) in the axial direction; Fig. Figure 5 shows in (a) and (b) each a section of a spoke rotor according to the invention; Fig. 6 shows a section through another embodiment of a spoke rotor according to the invention in the axial direction; Fig. 7 shows in (a) - (c) sectional views of a further embodiment of a spoke rotor according to the invention; and Fig. Figure 8 shows a section through a fully coated pole ring.

[0038] Fig. 1 shows a pole ring 1 for a spoked rotor 10 according to the invention. The pole ring 1 has a plurality of sectors 11.i made of a ferromagnetic material and provided for conducting a magnetic flux (not shown). Between adjacent sectors 11.i, a permanent magnet 2.i is arranged, which is provided for generating the magnetic flux. The permanent magnets 2.i are cuboid-shaped and extend in an axial direction 31 to an axis 30. The sectors 11.i taper counter to a radial direction 32 to the axis 30 such that the pole ring 1 formed from the sectors 11.i and the permanent magnets 2.i extends concentrically around the axis 30. The permanent magnets 2.i are held in the radial direction 32 by retaining webs 12, which are arranged on both sides of the sectors 11.i on an outer side 161 of the sectors 11.i facing away from the axis. The retaining webs 12 extend in the axial direction 31. Since the adjacent sectors 11.i are spaced apart from one another in the circumferential direction 33 by the permanent magnets 2.i, a groove-shaped free space 14 is formed between the holding webs 12.

[0039] On an inner side 162 of the pole ring 1 facing away from the axis, the sectors 11.i each have a form-locking means 13. The form-locking means 13 is designed here as a dovetail-shaped groove. It is used for the form-locking connection of a fastening means 4 (see Fig. 3, Fig. 4) with the pole ring 1.

[0040] Fig. 1 (a) shows an embodiment of such a pole ring 1 in a perspective view, in which, to reduce the torque ripple of a spoked rotor 11 comprising the pole ring 1, a gap filler 6 is arranged on a first side 201 of each permanent magnet 2.i between the permanent magnet 2.i and the sector 11.i adjacent to this side 201. An elastic or elastic-plastic filler (not shown) is preferably provided on a second side 202 opposite the first side 201.

[0041] The pole ring 1 of the Fig. 1 (b) has such a gap filler 6 on the second side 202 of the permanent magnet 2.i. Furthermore, this pole ring 1 is surrounded by a sleeve 5 that protects it against centrifugal forces. The sleeve 5 is designed, for example, as a plastic film.

[0042] The pole ring 1 of the Fig. 1 (c) does have such a sleeve 5, but no gap fillers 6. In addition, the sleeve 5 of this pole ring 1 does not extend over the entire axial length L1 of the pole ring 1.

[0043] In all three versions of the Fig. 1, the sectors 11.i are formed from a solid body, or from identical lamellae (not designated), which are connected to each other, for example, by punching and stacking.

[0044] Fig. 2 shows the arrangement of the permanent magnet 2 and the gap filler 6 on opposite sides 151, 152 of a sector 11. In Fig. 2 (a) the arrangement is shown exploded, and in Fig. 2 (b) in abutting, assembled state.

[0045] The permanent magnet 2 is arranged on a first side 151 of the sector 11. The gap filler 6 is arranged on the second side 152 of the sector 11, opposite the first side 151. Therefore, in the assembled state of the pole ring 1, a permanent magnet 2, a sector 11, and a gap filler 6 are always arranged alternately.

[0046] Fig. 2 (c) shows an embodiment of the form-locking means 13. It shows a plane of symmetry spanned by the axial direction and a radial direction.

[0047] It is visible that the form-locking means 13 is dovetail-shaped. However, it is asymmetrical to the plane of symmetry S. Specifically, a contour 131 of the form-locking means 13 is shifted inwards compared to a symmetrical contour 131' of the form-locking means 13. The shift is shown schematically by arrows 7. Due to such asymmetry, the sector 11 is arranged at a slight angle (not shown) to the radial direction 32. It has been shown that an air gap (not shown) between the sector 11 and adjacent permanent magnets 2i (see Fig. 1) can be reduced and the flow losses are reduced.

[0048] Fig. 3 shows a first embodiment of a spoke rotor 10 according to the invention. The spoke rotor 10 is in the Fig. 3 (a) shown in a perspective view. Fig. 3 (b) shows the spoke rotor 10 in a sectional view transverse to the axis 30, Fig. 3 (c) in a cross-sectional view along axis 30.

[0049] The rotor 10 also has a pole ring 1, which is formed from a plurality of sectors 11.i and permanent magnets 2.i arranged between the sectors 11.i. In contrast to the pole rings 1 of the Fig. 1, however, intermediate lamellae 9 are provided between the lamellae 19 with retaining means 12 arranged on both sides of the sectors 11.i. The intermediate lamellae 9 have transverse webs 91 on the outer side 161 of the sectors 11.i facing away from the axle or shaft. This provides greater stability to the spoked rotor 10, and the permanent magnets 2.i are additionally secured.

[0050] A shaft 3 is arranged centrally in the pole ring 1 and extends in the axial direction 31 and concentrically to the axis 30. The shaft 3 has a shaft shoulder 34. In the area of ​​the shaft shoulder 34, a diameter D wthe shaft 3 is larger than its diameter D1, D2 outside the shaft shoulder 34. The pole ring 1 is connected to the shaft 3 in a rotationally fixed manner in the area of ​​the shaft shoulder 34.

[0051] For this purpose, a fastening element 4 made of a first cured (curable) compound is arranged between the pole ring 1 and the shaft 3. In the illustrated embodiment, the fastening element 4 is at least partially designed as a spoke. The spokes 41 extend in the radial direction 32. They are spaced apart from one another. Furthermore, they are evenly distributed in the circumferential direction 33.

[0052] Between the spokes 41, receptacles 8 are arranged, which are empty here, or rather, filled with air. Since the gap (not marked) between the pole ring 1 and the shaft 3 is only partially filled with the fastening means 4, the spoke rotor 10 of this embodiment is relatively light. It has also been shown that the arrangement of the spokes 41 ensures very good stability and concentricity of the spoke rotor 10.

[0053] To fasten the pole ring 1 to the shaft 3, the positive locking means 13 provided on the inner side 162 of the pole ring 1 facing the shaft 3 (or axis 30) are also arranged here. They are aligned with the spokes 41 and are essentially filled with the hardened mass of the fastening means 4. In addition, the fastening means 4 extends over the entire surface of the inner side 162 of the pole ring 1 facing the shaft. This secures the permanent magnets 2.i against displacement against the radial direction 32. The first hardened mass is elastic or elastic-plastic for this purpose in order to exhibit sufficient spring behavior and / or mechanical clamping behavior. The fastening means 4 is therefore annular on the inner side 162 of the pole ring 1 facing the shaft.In the following, the annular region of the fastening means 4 arranged on the inner side 162 of the pole ring 1 is referred to as the outer ring 43 of the fastening means 4.

[0054] The shaft 3 also has second positive locking means 35. The second positive locking means are designed here as knurling. The second positive locking means 35 are arranged on an outer side 36 of the shaft 3 facing the pole ring 1. Furthermore, the shaft 3 is completely surrounded by the fastening means 4, so that the fastening means 4 engages in the knurling 35 and interacts with it when the shaft 3 rotates. The fastening means 4 is therefore annular on the outer side 36 of the shaft 3 facing the pole ring 1. In the following, the annular region of the fastening means 4 arranged on the outer side 36 of the shaft 3 is referred to as the inner ring 42 of the fastening means 4. The spokes 41 extend in the radial direction 32 between the inner ring 42 of the fastening means 4 and the outer ring 43 of the fastening means 4.

[0055] At its opposite ends 101, 102 in the axial direction 31, the spoke rotor 10 has end faces 111, 112. The end faces 111, 112 extend transversely to the axis 30. The fastening means 4 extends almost completely over the end faces 111, 112. It therefore extends in the region of the pole ring 1 in a ring shape along the end face 111, 112. This region of the fastening means is referred to below as the end ring 44. Furthermore, in the embodiment of the spoke rotor 10 shown here, it extends beyond the shaft shoulder 34 in the axial direction 31 at least at the first end 101. At the second end 102, however, it is provided flush with the shaft shoulder 34. At the first end 101, the fastening means 4 therefore extends at least partially in a ring shape in the region of the shaft shoulder 34 along the end face 111, 112. This region is referred to below as the end edge 46.

[0056] The permanent magnets 2.i are secured against displacement in and against the axial direction 31 by the end ring 44 arranged at both ends 101, 102 of the spoke rotor 10.

[0057] Furthermore, the fastening means 4 has intermediate webs 45 approximately in the center of the spoke rotor 10, which extend transversely to the axis 30 and divide the receptacles 8 in the axial direction 31. The intermediate webs 45 also increase the stability of the spoke rotor 10.

[0058] The spoke rotor of the Fig. 4 differs from that of the Fig. 3 in that a second (hardenable), hardened mass 40 is arranged in the receptacles 8. The second hardened mass 40 is arranged in the receptacles 8 after the first hardened mass of the fastening means 4 has hardened. It can be made of the same material as the first hardened mass. However, it is preferred that it be lighter than the first hardened mass and / or expand more during hardening. As a result, the permanent magnets 2.i are additionally pressed against the holding webs 12 and / or transverse webs 91.

[0059] Furthermore, it can be seen here that the fastening means 4 does not have any intermediate webs 45 that divide the receptacles 8 in the axial direction 31. The spoke rotor 10 of this embodiment therefore has receptacles 8 that extend over the entire axial length L1 of the spoke rotor 10.

[0060] Fig. Figure 5 shows in (a) a section of a spoked rotor 10, in which the fastening element 4 arranged between the pole ring 1 and the shaft shoulder 34 is arranged flush with the shaft shoulder 34. This fastening element 4 therefore has no end edge 46. Visible are the inner ring 42, the spokes 41, and the end ring 44 of the fastening element 4.

[0061] In the spoke rotor 10 of the Fig. 5 (b), the spokes 41 are arranged slightly obliquely relative to the radial direction 32. For clarity, this is exaggerated here. As a result, the spokes 41 have an acute angle 48 of preferably approximately 1° - 20°, particularly preferably approximately 2° - 8°, to the radial direction 32. The sectors 11.i are thereby drawn at an angle 48 relative to the shaft 3. It has been shown that this reduces an air gap (not shown) between the permanent magnets 2.i and the adjacent sectors 11.i, and the flux losses are therefore very low.

[0062] In the spoke rotors 10 described so far, the pole ring 1 is not completely covered. In contrast, the Fig. 6 a spoked rotor 10 with a fully coated pole ring 1.

[0063] In this spoked rotor 10, the fastening element 4 is annular on the outer side 161 of the pole ring 1, facing away from the shaft. It extends over the entire axial length L1 of the spoked rotor 10. The annular region of the fastening element 4 arranged on the outer side 161 of the pole ring 1 is referred to below as the outer casing 47 of the fastening element 4. The outer casing 47 is round here. This ensures high mechanical strength.

[0064] Also visible are recesses 163 on the outer casing 47, which are due to manufacturing.

[0065] Fig. 7 shows in (a) - (c) each a further embodiment of a spoke rotor 10 according to the invention.

[0066] The spoke rotor 10 of the Fig. 7 (a) differs from that of the Fig. 6 in that it has a sleeve 5, which is arranged on the outer side 48 of the fastening means 4 facing away from the shaft, i.e., on the outer casing 47. Furthermore, the second cured mass 40 is arranged in the receptacles 8 of this spoke rotor 10.

[0067] The spoke rotor 10 of the Fig. 7 (b) does indeed include the sleeve 5. However, no second cured compound 40 is provided in the receptacles 8. Furthermore, the fastening means 4 of this spoke rotor 10 includes the intermediate webs 45 between the receptacles 8, which are arranged in alignment with one another in the axial direction 31.

[0068] And the spoke rotor 10 of the Fig. 7 (c) differs from the spoke rotor 10 of the Fig. 7 (b) only in that it does not have a sleeve 5.

[0069] Fig.Figure 8 shows a section through a fully enclosed pole ring 1 of a spoked rotor 10, in which the shaft 3 and the pole ring 1 are connected to each other by a connecting sleeve (not shown), preferably manufactured independently of the pole ring 1. A conventional shaft, particularly a hollow shaft, can be used for such a separately manufactured pole ring. The shaft can be mounted, for example, using a shrink fit.

[0070] The permanent magnets 2.i of the spoke rotor 10 according to the invention can be positioned very precisely during production. The spoke rotor 10 therefore has very small cogging torques. Furthermore, an injection mold for producing such a spoke rotor 10 according to the invention is relatively simple in design and can therefore be manufactured cost-effectively.

Claims

[1] Spoke rotor (10) for an electrical machine, comprising a pole ring (1) and a shaft (3) arranged in the pole ring (1), which extend concentrically around an axis (30) and are spaced apart from one another, wherein the pole ring (1) has a plurality of sectors (11.i) between which permanent magnets (2.i) are arranged, and wherein a fastening means (4) is provided between the shaft (3) and the pole ring (1), which fastening means is formed from a first hardened mass, wherein • the fastening means (4) is at least partially spoke-shaped, wherein the spokes (41) extend in a radial direction (32), or substantially in the radial direction (32), to the axis (30); and / or • the pole ring (1) is completely surrounded by the fastening means (4), • characterized bythat the spoke rotor (10) has end faces (111, 112) at opposite ends (101, 102) in the axial direction (31), wherein the fastening means extends substantially over the entire surface along the end faces (111, 112). [2] Spoke rotor (10) according to claim 1, characterized by that the spokes (41) are evenly distributed in the circumferential direction (33). [3] Spoke rotor (10) according to one of the preceding claims, characterized by that receptacles (8) are arranged between the spokes (41). [4] Spoke rotor (10) according to one of the preceding claims, characterized by that a second hardened mass (40) is arranged in the receptacles (8). [5] Spoke rotor (10) according to one of the preceding claims, characterized by that the second cured mass (40) has a lower weight than the first cured mass (4) and / or expands during curing. [6] Spoke rotor (10) according to one of the preceding claims, characterized by that the fastening means (4) forms end rings (44) at both ends (101, 102) which secure the permanent magnets (2) against displacement in the axial direction (31). [7] Spoke rotor (10) according to one of the preceding claims, characterized by that the shaft (3) has a shaft shoulder (34). [8] Spoke rotor (10) according to one of the preceding claims, characterized by that the fastening means (4) is arranged flush with the shaft shoulder (34) or extends beyond the shaft shoulder (34) in an axial direction (31). [9] Spoke rotor (10) according to one of the preceding claims, characterized by that on a first side (201) of each permanent magnet (2.i) a gap filler (6) is arranged between the permanent magnet (2.i) and the sector (11.i) adjacent to this side (201). [10] Spoke rotor (10) according to one of the preceding claims, characterized bythat an elastic or elastic-plastic filler is attached, in particular glued or injection-molded, to a second side (202) opposite the first side (201) of each permanent magnet (2.i). [11] Spoke rotor (10) according to one of the preceding claims, characterized by that a sleeve (5) is arranged on an outer side (161) of the overmolded or non-overmolded pole ring (1) facing away from the shaft. [12] Spoke rotor (10) according to one of the preceding claims, characterized by that the fastening means (4) on the outer side (161) of the fully overmolded pole ring (1) facing away from the shaft is round or wavy. [13] Spoke rotor (10) according to one of the preceding claims, characterized by that form-locking means (13) are provided on the sectors (11.i), in particular recesses or grooves which are provided for receiving the first curable mass (4) and are designed asymmetrically. [14] Electric machine, in particular electric motor, with a spoke rotor (10) according to one of the preceding claims. [15] Adjustment drive, in particular for a motor vehicle, with an electric machine according to claim 14.

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