Cooled wheel for actively cooling stator of electric motor

Abstract

The invention relates to a cooling wheel (1) for actively cooling a stator (2) of an electric motor (3), the cooling wheel (1) being fixable adjacent to the stator (2) and rotationally fixed to a rotor (4) of the electric motor (3), which rotor is rotatable about an axis of rotation (A), and having a base disc (10) extending orthogonally to the axis of rotation (A), according to the invention, the base disc has an annular radially inner section (12) and a radially outer section surrounding the radially inner section in an annular manner, according to the invention, the cooling wheel (1) has, in the radially outer section axially adjacent to the base disc (10), a cover disc (30) surrounding the axis of rotation (A) in an annular manner and a plurality of blades (20) extending from the base disc (10) to the cover disc (30) and extending radially outwards, a respective flow channel being formed between each two directly adjacent blades (20), according to the invention, the two blades (20) are arranged on the base disc (10) and the cover disc (30), the flow channel is defined by the two blades (20), a corresponding section (11) of the base disc (10) between the two blades and a corresponding section (31) of the cover disc (30) between the two blades (20), each section (31) of the cover disc (30) is arc-shaped in the circumferential direction (U), and the outer circumference (32) of the cover disc (30) has a wave-shaped course.

Description

[0001] manual:

[0002] The invention relates to a cooling wheel for actively cooling the stator of an electric motor with stator electronics, and to an electric motor with such a cooling wheel.

[0003] Numerous solutions for cooling the stator of an electric motor are known from the prior art. Usually only passive cooling is provided, wherein the stator has cooling fins, for example, through which heat is dissipated to the environment without a defined fluid flow, in particular without generating an air flow over these cooling fins.

[0004] This solution is subject to many restrictions, since without a defined flow defined cooling can only be achieved to a limited extent.

[0005] Alternatively, the concept of active cooling is also known in the prior art, for example from DE 10 2012 107 109 A1, in which a fluid flow, ie an air flow, is actively generated and used to cool the stator.

[0006] However, especially at high or increasing speeds, the noise development and torque requirements of such cooling wheels can become unfavorable and lead to reduced efficiency and high noise levels.

[0007] The object of the present invention is therefore to overcome the above-mentioned disadvantages and to provide a cooling wheel for actively cooling the stator of an electric motor which has the lowest possible torque requirement and the lowest possible noise emissions even at high rotational speeds.

[0008] This object is achieved by the combination of features described in patent claim 1 .

[0009] Therefore, according to the present invention, a cooling wheel for actively cooling the stator of an electric motor is proposed, wherein the electric motor is particularly an external rotor type electric motor. In order to cool the stator, the cooling wheel can be fixed in a torsion-proof manner on the rotor of the electric motor that can rotate around the rotation axis, adjacent to the stator. The electric motor is preferably a motor of a fan, so that in addition to the cooling wheel, an impeller can also be provided on the rotor. According to the present invention, the cooling wheel has a base disk extending orthogonally to the rotation axis, the base disk has an annular radial inner section and an annular radial outer section, and the annular radial outer section surrounds the annular radial inner section in an annular manner. In the axial direction, that is, in the direction of the rotation axis or an axis parallel to the rotation axis, the cooling wheel also has a cover disk adjacent to the radial outer section of the base disk, the cover disk surrounds the rotation axis in an annular manner, and the cooling wheel also has a plurality of blades, which extend from the base disk to the cover disk and extend radially outward. Observed from the side of the cover disk, the radial outer section of the base disk preferably corresponds to the projection of the cover disk on the base disk. A flow channel is formed between every two directly adjacent blades, and the flow channel is defined by the two directly adjacent blades, the base plate section located between the two blades, and the cover plate section located between the two blades. Therefore, the cooling wheel has a large number of adjacent flow channels in the circumferential direction, and these flow channels are defined by the two blades, the cover plate, and the base plate, respectively. In order to reduce noise emission, especially in the case of high-speed operation, the corresponding section of the cover plate is configured to be arc-shaped or curved in the circumferential direction, so that the outer circumference of the cover plate has a wavy course in the circumferential direction.

[0010] In particular, the curvature can be convexly configured so that the cover disk section which spans the interval between two directly adjacent blades and thus defines the respective flow channel is curved outwards or towards the stator starting from the base disk.

[0011] The cooling wheel is preferably made of plastic, in particular by die-casting. In order to avoid complex production tools, for example tools requiring a large number of slides, it is preferably provided that the base disk and the cover disk are formed separately and then joined together. In this case, the blades can be produced in one piece with the base disk or the cover disk. The cover disk and the base disk can then be joined together, for example by hot stamping, with the blades being formed on each of the cover disk and the base disk, so that the cooling wheel is formed as a whole.

[0012] In this case, the term stator is also understood to mean, in particular, a stator bushing, on which the cooling fins mentioned below are formed and which, as a housing, surrounds other components of the stator, such as the stator electronics.

[0013] The stator has, in particular, a stator bushing with stator core laminations and also stator electronics, wherein the stator electronics is a control unit for controlling the electric motor.

[0014] In order to optimize the flow on the suction side, it can also be provided that the radially inner section of the base disk and the axially adjacent region are free of blades and cover disks, in particular also free of other flow obstacles. In this case, the radially inner section can be arranged axially adjacent to the stator, wherein the blades are designed to convey the fluid, in particular air, from the radially inner section of the base disk as the suction side of the stator through the flow channels formed by the blades toward the radially outer side and in particular the radially adjacent environment as the pressure side.

[0015] The radially inner section of the base can be further optimized in terms of flow technology by forming or providing a continuous transition from the radially outer side to the radially inner side and from a section of the base that is substantially orthogonal to the axis of rotation to a section of the base that is substantially parallel to the axis of rotation at the radially inner section of the base, which section of the base that is substantially orthogonal to the axis of rotation can be a radially outer section of the base. In this case, a continuous suction profile is formed by the transition. The radially inner section can accordingly have a concave course from the radially outer side to the radially inner side, as seen in a longitudinal section along the axis of rotation.

[0016] For the corresponding sections defining the flow channel on the cover disk, their respective curvatures may also increase from the radial inside to the radial outside. In the circumferential direction, the curvature on the inner circumference of the cover disk may be, for example, 0 and increase radially outward.

[0017] In the circumferential direction, the curvature of each segment or generally the arc segment preferably has a maximum value with respect to its course, and this maximum value is preferably arranged symmetrically on each flow channel in the circumferential direction. However, alternatively, multiple maximum values ​​and / or an asymmetrical arrangement of maximum values ​​are also feasible.

[0018] Preferably, the radially inner section of the base disk has a continuous course, ie without edges and jumps, in particular without flow obstacles.

[0019] In order to fasten the cooling wheel to the rotor, fastening elements can be arranged in the radially inner section of the base plate. For example, through-holes can be provided in the base plate, through which screws are inserted as fastening elements. The cooling wheel or the base plate of the cooling wheel can be fastened to the rotor or to a flange ring that can be fastened to the rotor by means of the fastening elements.

[0020] The fastening elements can also be arranged on the inner circumference of the base disk.

[0021] For example, the fastening element may be a screw or a locking element.

[0022] In particular, if locking elements are provided on the radially inner section of the base disk, these can adjoin spring elements on both sides in the circumferential direction, which are designed to compensate for tolerances and to fix the cooling wheel to the rotor or the flange ring without play.

[0023] In order to prevent, for example, screw heads or, in general, fastening elements from forming flow obstacles in the radially inner section of the base disk, a cover element can be arranged on the surface of the base disk on the cover disk side, adjacent to the fastening element, which surface faces the stator in the electric motor. The cover element is designed to cover the fastening element on the surface on the cover disk side and to provide a continuous, in particular flush, and thus flow-optimized course on the surface of the base disk on the cover disk side.

[0024] It is further preferred that the cover elements or the respective cover element can be designed to be surface-integrated, so that the cover disk side surface of the base disk transitions into the cover disk side surface of the respective cover element without a jump.

[0025] A groove may also be provided in or on the radially inner section of the base disk, the groove forming a recess relative to the cover disk side surface of the base disk, in which the fastening element may be arranged at least partially in a sunken manner. For example, the screw head of a screw used as a fastening element may be sunken in the recess. In general, the groove or recess may allow the fastening element to be arranged completely below the cover disk side surface of the radially inner section of the base disk.

[0026] In particular, if the cooling wheel is arranged on a fan or an electric motor of the fan, a variant is advantageous in which the base disk has a connection interface for connecting the impeller on the side facing away from the cover disk. The connection interface can be designed in particular as a bolt extending parallel to the axis of rotation or as a pocket formed in the base disk for accommodating an insert nut.

[0027] If the cooling wheel is not fastened directly to the rotor but, for example, via an annular flange on the rotor, the bolts extending parallel to the axis of rotation or in the axial direction can also be formed on the annular flange or integrated into the annular flange.

[0028] In particular, the screws can also be designed as threaded screws.

[0029] In order to optimize the flow generated by the blades, the blades preferably have a sickle-shaped blade geometry and are curved in the circumferential direction from the radial inside to the radial outside. The blades are preferably curved forwards. The sickle-shaped blade geometry is particularly advantageous if the rotor or cooling wheel has a single predetermined direction of rotation.

[0030] If, on the other hand, the rotor or the cooling wheel can be driven in both directions of rotation, so that the cooling wheel is designed to rotate both clockwise and counterclockwise, the blades preferably have a straight or only slightly curved geometry.

[0031] One aspect of the present invention also relates to an electric motor having a stator, a rotor rotatable about an axis of rotation, and a cooling wheel arranged on the rotor according to the present invention for cooling the stator. The stator and the rotor are preferably arranged axially in sequence, wherein the electric motor is in particular an outer rotor type electric motor. In addition, preferably, the electric motor can also be a motor of a fan, which can have an impeller connected to the rotor at the rotor. The cooling wheel is axially arranged at an end section on the stator side of the rotor and is directly adjacent to the stator through a radially inner section of the base disk, so that when the rotor rotates, a fluid flow is generated that flows axially from the stator section adjacent to the radially inner section of the base disk through the flow channel toward the radial outward.

[0032] Furthermore, the cooling wheel can be fixed directly to the rotor via its base plate. Alternatively, the cooling wheel can be fixed via its base plate to a flange ring, which is fixed to the rotor. If such a flange ring is provided, bolts, in particular threaded bolts, can be arranged on it remote from the cooling wheel in order to fix, for example, an impeller to the flange ring. Alternatively, grooves corresponding to the connection interface of the base plate can also be provided on the flange ring so that a fastening means for fastening, for example, an impeller can be screwed into the connection interface of the cooling wheel base plate via the groove.

[0033] To improve the cooling effect, the stator and in particular the stator bushing of the stator can have cooling fins distributed in the circumferential direction around the rotation axis, which are arranged axially directly adjacent to the radial inner section of the cooling wheel and in particular extend in the radial direction.

[0034] The cooling wheel also preferably defines a suction chamber in a radially inner section of the base disk, which suction chamber is delimited by the base disk, the blades and the cover disk, surrounds the rotation axis in an annular shape and is open toward the stator, wherein the cooling fins protrude into the suction chamber.

[0035] An advantageous further development also provides that the cooling wheel and in particular the base disk forms a labyrinth seal with the stator on the radial inner circumference.

[0036] As long as it is technically feasible and not contradictory, the features disclosed above can be combined as needed.

[0037] Other advantageous further developments of the invention are described in the dependent claims and are described in detail below together with the description of preferred embodiments of the invention with reference to the accompanying drawings. Among them:

[0038] Figure 1 An electric motor with a cooling wheel for a fan is shown;

[0039] Figure 2a to Figure 2c Various views showing a first variant of a cooling wheel;

[0040] Figure 3a to Figure 3d Various views showing a second variant of a cooling wheel;

[0041] Figures 4a to 4d Various views showing a third variant of a cooling wheel;

[0042] Figure 5a to Figure 5c Various views showing a fourth variant of a cooling wheel;

[0043] Figure 6 A perspective view showing a fifth variant of the cooling wheel, wherein a part is shown enlarged;

[0044] Figure 7 A side view of a first variant of the electric motor is shown, with a portion shown enlarged and showing details;

[0045] Figure 8 A side view of a second variant of the electric motor is shown, with a portion shown enlarged and showing details;

[0046] The accompanying drawings are schematic examples. The same reference numerals in the accompanying drawings represent the same functions and / or structural features.

[0047] Figure 1 An overall view of an electric motor 3, in particular an electric motor 3 for a fan, is shown, so that its stator 2, rotor 4 and cooling wheel 1 can be seen. The rotor 4 can rotate about an axis of rotation A, wherein the cooling wheel 1 is fixed to the rotor 4 in the axial direction, i.e., along the axis of rotation A, between the rotor 4 and the stator 2 and thus rotates together with the rotor 4 about the axis of rotation A. In this case, the cooling wheel 1 actively generates an air flow from the radial inside to the radial outside. Therefore, the cooling wheel 1 has a suction side on the radial inside adjacent to the stator 2 and a pressure side on the radial outside or the outer circumference of the cooling wheel 1. Therefore, air is actively sucked in through the stator 2 and blown out radially outward.

[0048] In particular, the stator 2 has stator electronics 7 installed therein and a stator bushing 8 , wherein cooling fins 60 are formed on the stator bushing 8 , which extend to or into the suction chamber of the cooling wheel 1 .

[0049] Figure 1 The cooling wheel 1 shown in the figure and all the cooling wheels shown in the other figures have a base disk 10, a plurality of impellers 20 and a cover disk 30. Figure 2a , Figure 2c , Figure 3a , Figure 3c , Figure 3d , Figure 4a , Figure 4c , Figure 5a , Figure 5c and Figures 6 to 8, it can be seen that the impeller 20 is arranged only in the radially outer section of the base disk 10, i.e. the section which is located on the outside in the radial direction R and surrounds the rotation axis A in a ring shape, and is covered axially or toward the stator by the cover disk 30. In each case, the radially inner section 12, i.e. the section which is located on the inside in the radial direction R and surrounds the rotation axis A in a ring shape, is provided without the impeller 20, the cover disk 30 and in particular without further flow obstacles, so that in the state arranged on the stator 2, a suction chamber which is open toward the stator 2 is formed in the radially inner section 12, through which air can be sucked in from the stator 2 in a flow-optimized manner.

[0050] In order to generate an optimized flow, the impellers 20 each have a sickle-shaped geometry and are preferably rotated in the opposite direction to the predetermined direction. A flow channel is formed between each two impellers 20 arranged directly adjacent to each other, which is bounded by the impellers 20 in the circumferential direction U and by a section 11 of the base disk 10 and a section 31 of the cover disk 30 in the axial direction. Therefore, the flow channel is open in the radial direction R.

[0051] Tests have shown that, in particular at high rotational speeds, the noise generated by the cooling wheel 1 is significantly reduced if the cover disk 30 is not designed to be flat, but rather has a wave-like shape in the circumferential direction U. Accordingly, it is provided that the sections 31 of the cover disk 30 that define each flow channel, that is, the sections 31 located between two directly adjacent impellers 20, are designed to be arc-shaped or curved. This results in a continuous alternation between maximum and minimum values ​​in the circumferential direction, thus forming a wave shape.

[0052] As shown in the corresponding figures, the cover disk 30 or its section 31 has no or only a minimal curvature on the inner circumference, which curvature increases radially outwards, ie in the radial direction R away from the axis of rotation A.

[0053] Although the transition between two segments 31 or the transition between two arcs defined by segments 31 may also be abrupt, it is preferably provided that the transition is continuous so that no edge is formed between the two segments 31 or between the two arcs defined by them, but a smooth transition is formed.

[0054] Figure 2a to Figure 2c A first variant of a cooling wheel 1 is shown. Here, Figure 2a A perspective view of the cooling wheel 1 in the assembled state, showing the side facing the stator 2, Figure 2b The side of the cooling wheel 1 facing the rotor 4 or facing away from the stator 2 is shown. Figure 2c An excerpt of a longitudinal section through the cooling wheel 1 along the axis of rotation A is shown.

[0055] like Figure 2cAs shown, the variant according to these figures is characterized in that the cooling wheel 1 can be fixed to the rotor 4 via an annular flange 5. For this purpose, a plurality of grooves 44 distributed in the circumferential direction are provided on the radial inner section 12, through which screws as fastening elements 40 can be screwed onto the annular flange 5. The grooves 44 are designed as countersunk through-holes or stepped through-holes, so that the screw heads of the screws at least partially sink into the base plate 10, forming a slight flow obstacle, which can be particularly effective from the Figure 2c It can be seen in.

[0056] In order to optimize the flow, it is also provided that the base disk 10 has a flow-optimized course from a radially outer section to a radially inner or inner section 12 toward the rotation axis A. This course is formed in that a continuous transition is formed from a section of the base disk 10 orthogonal to the rotation axis A to a section 13 of the base disk 10 parallel to the rotation axis A, thereby forming a concave course, wherein the section of the base disk 10 orthogonal to the rotation axis A corresponds essentially to the radially outer section in the present case. Along this transition, the air sucked in through the stator 2 is deflected in the flow path direction and accordingly radially outwards.

[0057] Furthermore, an annularly circumferential groove 14 and an annularly circumferential projection 15 are formed adjacent to the radial inside, which together with associated elements of the stator form a labyrinth seal 6 .

[0058] Figure 3a to Figure 3d An alternative variant is shown, in which Figure 3a The stator side view is shown again, and Figure 3b A side view of the rotor is shown.

[0059] As in particular Figure 3a , Figure 3c and Figure 3d As shown in FIG, a screw is again used as a fastening element 40, wherein the recess 44 is designed to be so deep that the screw head is completely sunken and lies below the surface determined on the stator side of the base plate 10. In order to further optimize the flow along this surface, a cover element 43 is also provided, wherein the cover element 43 closes the recess 44 and covers the screw or fastening element 40 accordingly. Figure 3c As shown, the cover element 43 is integrated in a surface-flush manner with the stator-side surface of the base disk 10 , so that this surface or the radially inner section 12 of the base disk 10 is free of flow obstacles.

[0060] If the cooling wheel 1 is Figure 3a to Figure 3dAs shown, preferably for the motor 3 of the fan, the impeller can also be fixed to the rotor 4 by means of the flange ring 5 not shown. For this purpose, a connection interface is provided on the base plate 10, and a pocket 50 is also provided here, in which an embedded nut is fixed. A corresponding opening is provided in the flange ring 5, so that the impeller can be arranged on the flange ring 5 and the embedded nut fixed in the pocket 50 can be screwed in through the opening. Alternatively, a screw or a screw head can also be embedded in the pocket, so that the thread of the screw passes through the flange ring 5.

[0061] Figures 4a to 4d The variant of the cooling wheel 1 shown is characterized in particular in that locking elements 41 are provided as fastening elements for fastening on the annular flange 5. These locking elements are designed in one piece with the base plate 10, but can also be provided separately.

[0062] like Figure 4c As shown, the locking element 41 passes through the annular flange 41 and is locked therewith by the elastic arm. In order to prevent the residual gap between the annular flange 5 and the base plate 10 that allows movement, it is also provided that the locking element 41 is adjacent to the spring element 45 on both sides of the circumferential direction U, as shown in FIG. Figure 4d The spring elements 45 are supported on the annular flange 5 respectively, so that the connection between the base plate 10 and the annular flange 5 is kept without gap through the locking element 41.

[0063] like Figure 4c As shown, in this variant, a transition from a radially outer section orthogonal to the axis of rotation A to a section 13 parallel to the axis of rotation A, a groove 14 and a projection 15 are also provided for producing a labyrinth seal 6 .

[0064] exist Figure 5a In the variant shown in FIG. 5 d , the cooling wheel 1 is not mounted or fixed on the annular flange 5 but directly on the stator-side end face of the rotor 4 . Figure 5c As shown, fastening elements designed as locking hooks 42 are provided on the inner circumference of the cooling wheel 1, which extend into the rotor 4 and lock thereon. It is particularly advantageous here that the fastening elements 40 do not need to be concealed or flow-optimized in the radial inner region 12, so that this region 12 has no flow obstacles.

[0065] Figure 6 The cooling wheel 1 is shown partially in section and an enlarged detail of the cooling wheel 1. Figure 3a to Figure 3d The illustrated variant differs in that the base disk 10 also forms pockets 50 for receiving insert nuts, which, however, are not sunken below the surface of the base disk 10 on the stator side, but rather protrude beyond the surface on the stator side.

[0066] The sickle-like shape of the blades 20, which is adapted to run counter to the direction of rotation, can be seen in particular through the cross-sectional views and partial enlargements, as indicated by the blades 20 in each of the embodiments shown.

[0067] Figure 7 and Figure 8 A side view of the electric motor 3 and an enlarged detail in the region of the cooling wheel 1 are respectively shown.

[0068] In particular, the enlarged sections show the labyrinth seal 6 , which is formed by the grooves 14 and the protrusions 15 of the base plate 10 and the surrounding protrusions 61 of the stator, thereby preventing foreign particles from penetrating into the interior of the motor 3 .

[0069] Furthermore, the two figures show that the stator 2 is constructed adjacent to the cooling wheel 1 with a multiplicity of cooling fins 60 which are distributed in the circumferential direction around the axis of rotation A and extend in the radial direction R.

[0070] exist Figure 7 In the embodiment, the cooling fins 60 are adjacent to an air intake chamber, which is formed in the area of ​​the radially inner section 12 of the base plate 10 and is open axially toward the stator 2, so that air can be sucked into the air intake chamber from between the cooling fins 60, wherein the air flowing along the cooling fins 60 cools the stator 2. Figure 7 The variant shown is preferably Figure 1 The motor 3 is shown.

[0071] exist Figure 8 In the illustrated embodiment, the cooling fins 60 are not only adjacent to the suction chamber, but also extend into the suction chamber.

[0072] The invention is not limited to the preferred embodiments described above. On the contrary, many variants are conceivable, and the solution shown can be used even in substantially different types of embodiments.

Claims

1. A cooling wheel (1) for actively cooling a stator (2) of an electric motor (3), in, The cooling wheel (1) can be fixed in a torque-proof manner adjacent to the stator (2) on a rotor (4) of the electric motor (3) which can rotate about an axis of rotation (A), and has a base plate (10) extending orthogonally to the axis of rotation (A), the base plate having an annular radial inner section (12) and a radial outer section surrounding the radial inner section in an annular manner, The cooling wheel (1) has a cover disk (30) annularly surrounding the rotation axis (A) and a plurality of blades (20) extending from the base disk (10) to the cover disk (30) and extending radially outward in the radially outer section axially adjacent to the base disk (10). A respective flow channel is formed between each two directly adjacent blades (20), and the flow channel is defined by the two blades (20), a corresponding section (11) of the base plate (10) located between the two blades, and a corresponding section (31) of the cover plate (30) located between the two blades (20). The individual sections (31) of the cover disk (30) are each configured to be arc-shaped along a circumferential direction (U), and the cover disk (30) has a wavy shape on its outer circumference (32).

2. The cooling wheel according to claim 1, in, The radially inner section (12) of the base plate (10) and the axially adjacent region are free of the blades (20) and the cover plate (30), and can be arranged adjacent to the stator (2), and the blades (20) are configured to transport fluid from the radially inner section (12) of the base plate (10) through flow channels formed by the blades and from the stator (2) radially outward.

3. The cooling wheel according to claim 1 or 2, in, A continuous transition portion from a section of the base disk (10) which is orthogonal to the rotation axis (A) to a section of the base disk (10) which is parallel to the rotation axis (A) is constructed on the radial inner section (12) of the base disk (10) from the radial outer side to the radial inner side, thereby forming a continuous suction profile through the transition portion.

4. A cooling wheel according to any one of the preceding claims, wherein: The curvature of each arc-shaped section (31) of the cover plate (30) increases from the radial inner side to the radial outer side.

5. A cooling wheel according to any one of the preceding claims, in, The radially inner section (12) of the base disk (10) has a continuous course and is in particular free of flow obstacles.

6. A cooling wheel according to any one of the preceding claims, in, Fastening elements (40, 41, 42) for fastening the base disk (10) to the rotor (4) or to a flange ring (5) that can be fastened to the rotor (4) can be formed or arranged in the radially inner section (12) of the base disk (10).

7. Cooling wheel according to the preceding claim, in, A cover element (43) is arranged on the surface of the cover plate side of the base plate (10) adjacent to the fastening element (40), the cover element being constructed to cover the fastening element (40) and providing a continuous and particularly surface-flush course relative to the surface of the base plate (10) on the surface of the cover plate side of the base plate (10).

8. A cooling wheel according to any one of the two preceding claims, in, A groove (44) is provided in a radially inner section (12) of the base disk (10), the groove forming a recess relative to a cover disk side surface of the base disk (10), in which the fastening element (40) can be arranged in a sunken manner.

9. A cooling wheel according to any one of the preceding claims, in, The base plate (10) has a connection interface for connecting an impeller on a side away from the cover plate (30). Therein, the connection interface is particularly configured as a bolt extending parallel to the rotation axis or as a pocket (50) for accommodating an embedded nut.

10. The cooling wheel according to any one of the preceding claims, in, The blades (20) have a sickle-shaped blade geometry and are curved from the radial inside to the radial outside in the circumferential direction.

11. An electric motor (3) having a stator (2), a rotor (4) rotatable about an axis of rotation (A), and a cooling wheel (1) arranged on the rotor (4) for cooling the stator (2) according to any one of the preceding claims, wherein: The electric motor (3) is in particular designed as an external rotor electric motor, and The cooling wheel (1) is arranged at the end section of the rotor (4) on the stator side in the axial direction and is directly adjacent to the stator (2) through the radial inner section of the base disk (10), so that when the rotor (4) rotates, a fluid flow radially outward through a flow channel is generated from the section of the stator (2) that is axially adjacent to the radial inner section (12) of the base disk (10).

12. Electric motor according to the preceding claim, in, The cooling wheel (1) is directly fixed on the rotor (4) via its base plate (10) Alternatively, the cooling wheel (1) is fixed via its base plate (10) to a flange ring (5), and the flange ring is fixed to the rotor (4).

13. A cooling wheel according to any one of the two preceding claims, in, The stator (2) has cooling fins (60) distributed around the rotation axis (A) in the circumferential direction, the cooling fins are arranged directly adjacent to the radial inner section (12) of the cooling wheel (1) in the axial direction, and extend in particular in the radial direction (R).

14. Electric motor according to the preceding claim, in, The cooling wheel (1) defines a suction chamber in a radially inner section (12) of the base disk (10), the suction chamber being defined by the base disk (10), the blades (20) and the cover disk (30), surrounding the rotation axis (A) in an annular shape and opening toward the stator (2), and the cooling fins (60) extending into the suction chamber.

15. An electric motor according to any one of claims 11 to 14, in, The cooling wheel (1), and in particular the base disk (10), forms a labyrinth seal (6) with the stator (2) on the radial inner circumference.

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