Stator device, electric machine, and compressor

Abstract

The invention relates to a stator device (3) for an electric machine (1), comprising a stator (8) which is cylindrical at least in some parts and which has at least one electrically conductive stator winding (10), wherein a respective winding head (11, 12) of the stator winding (10) protrudes from both axial end faces of the stator, and at least one of the winding heads is encased by a cylindrical shell-shaped impregnation (13). According to the invention, at least one end face of the impregnation (13) is equipped with a first cooling air guiding structure (15) comprising at least one air guiding channel (17) which extends from the exterior to the interior of the impregnation (13) at least substantially in the radial direction and which is at least substantially open towards the first end face.

Description

[0001] Description

[0002] title

[0003] Stator device, electric machine and compressor

[0004] The invention relates to a stator device for an electrical machine, comprising a stator which is at least partially cylindrical in shape and has at least one electrically conductive stator winding, wherein the winding heads protrude from both axial end faces of the stator, each with a winding head, and wherein at least one of the winding heads is covered by a cylindrical impregnation

[0005] Furthermore, the present invention relates to an electric machine for a motor vehicle, in particular a drive machine, with a rotatably mounted rotor with a stator device associated with the rotor.

[0006] Furthermore, the present invention relates to an electric compressor, in particular for a fuel cell, having a compressor wheel which is rotatably mounted in a compressor chamber and is operatively connected to an electric machine.

[0007] State of the art

[0008] Stator devices of the type mentioned above are already known from the prior art. For example, published patent application EP 2 887 507 A1 discloses a method for impregnating a stator. Impregnation protects, in particular, the stator winding and increases the service life of the electrical machine with such a stator device.

[0009] Disclosure of the invention The stator device according to the invention with the features of claim 1 has the advantage that the stator device ensures improved cooling of the stator device and of an electrical machine having the stator device. By advantageously utilizing the impregnation, it is achieved that, for example, advantageous cooling of the air gap between the stator and rotor takes place, whereby the electrical machine with this stator device achieves improved efficiency. According to the invention, it is provided for this purpose that a first cooling air guide structure with at least one air guide channel extending at least substantially radially from an outer side to an inner side of the impregnation and at least substantially open towards the first end side is formed in the impregnation on at least one first axial end face.The stator device is, in particular, cylindrical overall, at least in sections, with the winding heads and thus the impregnation on the winding heads also being cylindrical. The outer side is understood to be the outer surface of the casing, and the inner side is understood to be the inner surface of the casing of the impregnation. Cooling air or a cooling air flow is thus guided through the first cooling air guidance structure to the inside of the stator or the stator device. As a result, the impregnation not only forms the known enclosure for protecting the stator winding, but also offers a structure that enables the targeted steering of a cooling air flow through the cooling air guidance structure integrated into the impregnation. This cooling air guidance structure ensures that a cooling air flow is directed to a desired location during operation.This way, without separate means, with a simple adjustment of the geometry of the impregnation during its production, the behavior of the electrical machine or the stator device in the electrical machine is advantageously influenced.

[0010] The cooling air guide structure is preferably designed to direct a cooling air flow radially inward, so that the cooling air flow reaches an air gap between the stator and the rotor of the electric machine over the shortest possible path when the stator device is installed as intended. Furthermore, it is preferably provided that the first cooling air guide structure is designed to redirect the cooling flow. The cooling air guide structure thus redirects the cooling air flow, for example, from a radial inflow direction into an axial or radial-axial or oblique outflow direction, in order to advantageously guide the cooling air flow into the interior of the stator, in particular into the air gap.

[0011] Particularly preferably, the cooling air guide structure has at least one air guide channel on each of the winding heads. Preferably, several air guide channels are arranged on the respective winding head, distributed over the circumference of the winding head, in order to achieve advantageous cooling of the stator device and the electric machine.

[0012] Preferably, the respective air duct extends through the impregnation at a distance from the stator winding, so that the sealing of the stator winding remains intact. The respective cooling air duct is created, particularly during the production of the impregnation, by a removable core in the shape of the subsequent air duct.

[0013] Preferably, the first cooling air guide structure is designed to redirect a cooling air flow toward the center of the stator. This ensures that, when installed in the electric machine, the cooling air flow is advantageously supplied to the air gap and the rotor. Optionally, air guide webs or ribs are arranged on the inside of the casing of the impregnation, which ensure that the respective cooling air flow exiting from the air guide channel is further directed.

[0014] According to a preferred development, the first cooling air guide structure has a flow guide element for deflection, which closes the first air guide channel toward the first end face and is oriented obliquely to the longitudinal extent of the remaining first air guide channel. Thus, the first air guide channel is only partially open toward the first end face. In the region of the flow guide element, the air guide channel is circumferentially closed, thus ensuring advantageous deflection of the cooling air flow through the flow guide element.

[0015] Preferably, a second cooling air guide structure is formed in the impregnation on the second end face of the impregnation. Optionally, the second cooling air guide structure is formed like the first, but is mirrored at a stator center plane that is perpendicular to the rotational or cylindrical axis of the stator device. Alternatively, the second cooling air guide structure differs from the first cooling air guide structure.

[0016] Preferably, the second cooling air guide structure comprises a second air guide channel extending from the outside to the inside of the impregnation.

[0017] In particular, the second air duct is closed or at least substantially closed toward the second end face. In one embodiment, the second air duct is thus completely closed on its periphery. Optionally, the second air duct also forms the deflection for the cooling air flow through a corresponding channel path.

[0018] Preferably, several of the air guide channels are formed on the first end face and / or the second end face and are arranged, in particular, evenly distributed over the circumference of the stator device. This advantageously increases the cooling performance of the stator device.

[0019] The electric machine with the features of claim 10 is characterized by the inventive design of the stator device. This results in the advantages already mentioned above.

[0020] In particular, the stator is mounted in a stator chamber of a housing of the electrical machine, wherein the housing has at least one inflow channel for cooling air, which opens into the stator chamber through an inflow opening, wherein the cooling air guide structure is assigned to the inflow opening, in particular opposite it, in order to advantageously forward the supplied cooling air flow.

[0021] The electric machine preferably has a cooling device, with the inflow channel passing through the cooling device. This ensures that the cooling air supplied to the stator device is cooled or can be cooled if necessary, thus contributing to high heat dissipation.

[0022] The compressor according to the invention with the features of claim 13 is characterized by the inventive design of the electric motor. This results in the advantages already mentioned above.

[0023] Preferably, an inlet opening of the inflow channel opens into the compressor chamber. Thus, the inflow channel leads from the compressor chamber to the stator device, optionally passing through the aforementioned cooling device. Thus, during operation of the electric compressor, the cooling air is taken from the compressor chamber or the compressor chamber. Because the air is compressed in the compressor chamber and thus has an increased air pressure, it is conveyed into the inflow channel during operation and thus to the stator device. This results in an advantageously high cooling capacity for the stator device.

[0024] Further advantages and preferred features and combinations of features emerge in particular from the above description and from the claims. The invention will be explained in more detail below with reference to the drawings.

[0025] The only figure shows an advantageous electric compressor with an electric machine in a simplified sectional view.

[0026] The single figure shows an advantageous electric machine 1 of an electric compressor 14 in a simplified sectional view, wherein only a part of the electric machine 1 is shown above a rotation axis 6. The electric machine 1 has a housing 2 in which a stator 3 is mounted in a rotationally fixed manner and a rotor 4 is mounted in a rotationally fixed manner. The rotor 4 is mounted on a rotor shaft

[0027] 5, whose rotation axis 6 is also shown in the figure.

[0028] The stator 3 is circularly cylindrical and surrounds the rotor 4 radially or is arranged coaxially with it. The rotor shaft 5 is advantageously held in the housing 2 by one or more rolling element bearings or other friction-reducing bearings.

[0029] The stator 3 is arranged in a stator chamber 7 of the housing 2. The stator device 3 comprises a stator 8, which is made in particular of metal and in particular has a plurality of stator teeth 9 arranged evenly distributed over the circumference of the stator and projecting radially inward. Furthermore, the stator device 3 comprises a stator winding 10, which has winding heads 11 and 12 projecting axially from the stator 8 on both sides.

[0030] Furthermore, the stator winding 12 has a coating in the form of an impregnation 13. The impregnation 13 is made, in particular, of an epoxy material, silicone, thermoplastic, and / or thermoset, and is produced, in particular, by a casting or injection molding process. The impregnation 13 completely surrounds, in particular, the winding heads 11 and 12, thereby advantageously protecting the stator winding 12 from external influences and damage. This advantageously increases the durability of the electrical machine 1.

[0031] On the axial end faces of the stator device 3, the impregnation 13 is manufactured with a thickness that is greater than the remaining impregnation thickness or thickness. In the area of ​​the winding overhangs 11, 12, the impregnation 13 each has a cooling air guide structure 15 and 16, respectively. The first cooling air guide structure has at least one first air guide channel 17, and the second cooling air guide structure 18 has at least one second air guide channel 18, each of which extends through the impregnation 13. The air guide channels 17 and 18 are designed differently in the present case. According to an alternative exemplary embodiment, the air guide channels 17, 18 are identical, although mirror-symmetrical to one another. In any case, a plurality of the air guide channels 17 and 18 are preferably present and are preferably arranged evenly distributed over the circumference of the stator device 3.

[0032] According to the present embodiment, the air guide channels 17, 18 each lead from an outer side 19 of the stator device 3 or the impregnation 13 to an inner side 20.

[0033] The housing 2 has a plurality of inflow channels 21, 22 leading into the stator chamber 7. The inflow channels 21, 22 open into the stator chamber through inflow openings 23, 24, which are assigned to the end faces of the stator device 3. The air ducts 17, 18 are designed such that their respective inlet openings 25, 26 are each opposite one of the inflow openings 23, 24, so that the supplied cooling air enters the respective air duct 17, 18 directly and is guided by it toward the rotor 4.

[0034] The air guide ducts 17, 18 each have a deflection 30, 31, through which the respective air flow is directed toward the rotor 4 or toward the stator center, as shown by arrows in the figure. As a result, the respective air flow reaches, in particular, the air gap 27 between the stator 8 and the rotor 4, thereby advantageously cooling the electric machine 1 during operation.

[0035] Optionally, at least the air guide channel 17 is also assigned an axial or lateral inflow opening 28 of a further inflow channel 29 of the housing 2, through which a cooling air flow can be supplied to the stator device.

[0036] Preferably, the electric machine also has a cooling device 32 located in the inflow channel 21, so that the supplied cooling air can be cooled as needed, thereby optimizing heat dissipation from the electric machine 1. An inlet opening 33 of the inflow channel preferably opens into a compressor chamber 34 of the compressor 14, in which a compressor wheel (not shown here) is rotatably mounted and connected to the rotor shaft 4 for its drive. During operation, this creates an overpressure in the compressor chamber 34, which drives air from the compressor chamber 34 through the inlet opening 33 into the inflow channel 33, optionally through the cooling device 32, and subsequently into the air guide channels 17, 18.

[0037] Optionally, cooling guide ribs (not shown here) are formed on the inner side 14 of the casing of the impregnation 13, which advantageously guide / direct the air flow in the direction of the rotor 4 or in the direction of the center of the stator 8.

[0038] Preferably, the cooling air guide structures 15, 16 are designed such that the cooling air is guided into areas of the electrical machine 1 that become particularly warm during operation, such as in particular the bearing points, the rotor 4 and / or the winding heads 11, 12.

[0039] The air duct 17 is open or at least substantially open towards the first end face of the stator device 3, so that a cooling air flow can enter the air duct 17 both through the inflow opening 23 and through the further inflow opening 28, which opens into the stator chamber 7 axially to the stator device 3. The air duct 17 also preferably has a varying depth along its longitudinal extent, with the depth increasing towards the inner side 20 in the axial direction of the stator device 3. The change in depth is formed in particular by a step 35, in particular by an inclined step 35 in the base of the air duct 17, which is set back from the end face and is located in particular opposite the inflow opening 28.As a result, the cooling air flowing axially through the inlet opening 28 into the air duct 17 is advantageously introduced or redirected into the air duct 17. Alternatively, the air duct 17 has a consistently constant axial depth in order to minimize the impact on the flow of cooling air.

[0040] Furthermore, a flow guide element 36 is assigned to the inner side 20 of the air duct 17. Like the step 35, this flow guide element is oriented obliquely to the longitudinal extent of the air duct 17 in order to redirect the cooling air flow in a preferred direction, namely toward the stator center, before it leaves the air duct 17. This advantageously directs the cooling air flow toward the rotor 4 or the stator center and the air gap 27. The flow guide element 36 also closes the air duct 17 at its end on the inner side 20, partially toward the first end face. Optionally, the flow guide element 36 can be omitted, so that the air duct 17 is entirely open toward the first end face.In contrast, the air guide duct 18 is completely closed on its circumference, but it also has a flow guide element 37, particularly at its end facing the inner side 20, for redirecting the cooling air flow toward the stator center. The two flow guide elements 36, 37 are characterized by a flow guide surface extending obliquely to the radial flow direction.

Claims

Claims 1. Stator device (3) for an electrical machine (1), comprising a stator (8) which is at least partially cylindrical in shape and has at least one electrically conductive stator winding (10), wherein the stator winding (10) protrudes on both axial end faces of the stator, each with a winding head (11, 12), and wherein at least one of the winding heads is encased by a cylindrical-shell-shaped impregnation (13), characterized in that a first cooling air guide structure (15) is formed in the impregnation (13) on at least a first end face, said first cooling air guide structure having at least one air guide channel (17) extending at least substantially radially from an outer side to an inner side of the impregnation (13) and at least substantially open towards the first end face.

2. Stator device according to claim 1, characterized in that the first cooling air guide structure (15) is designed to guide a cooling air flow at least substantially radially inwards.

3. Stator device according to one of the preceding claims, characterized in that the first cooling air guide structure (15) is designed to deflect the cooling air flow towards a stator center.

4. Stator device according to one of the preceding claims, characterized in that the first cooling air guide structure (15) has a flow guide element (36) for deflection, which guides the first air guide channel (17) closes towards the first end face.

5. Stator device according to one of the preceding claims, characterized in that a second cooling air guide structure (16) is formed in the impregnation (13) on a second end face of the impregnation (13).

6. Stator device according to one of the preceding claims, characterized in that the second cooling air guide structure (16) has a second air guide channel (18) which extends from the outer side (19) to the inner side (20) of the impregnation (13) 7. Stator device according to one of the preceding claims, characterized in that the second air guide channel (18) is closed or at least substantially closed on the circumference, in particular towards the second end face 8. Stator device according to one of the preceding claims, characterized in that the second air guide channel (17, 18) forms a deflection in the direction of a center point of the stator (8) 9. Stator device according to one of the preceding claims, characterized in that a plurality of the air guide channels (17, 18) are formed on the first end face and / or on the second end face of the impregnation (13) and are arranged in particular uniformly distributed over the circumference of the stator device (3).

10. Electrical machine (1) for a motor vehicle, in particular a drive machine, with a rotatably mounted rotor (4) and a stator device (3) associated with the rotor (4), characterized by the design of the stator device (3) according to one of claims 1 to 9.

11. Electrical machine (1) according to claim 10, characterized in that the stator device (3) is mounted in a stator chamber (7) of a housing (2) of the electrical machine (1), wherein the housing (2) has at least one inflow channel (21, 22, 29) for cooling air, which opens into the stator chamber (7) through an inflow opening (23, 24, 28), and that the respective cooling air guide structure (15, 16) is opposite at least one inflow opening (23, 24, 28).

12. Electrical machine according to claim 11, characterized in that a cooling device (32) is provided, and that at least one inflow channel (21) leads through the cooling device (32).

13. An electric compressor (14), in particular for a fuel cell, comprising a compressor wheel which is rotatably mounted in a compressor chamber (34) and is operatively connected to an electric machine (1), characterized by the design of the electric machine according to one of claims 10 to 12.

14. Electric compressor according to claim 10, characterized in that an inlet opening (33) of an inflow channel (29) opens into the compressor chamber (34).

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