Rotor for electric traction motor

Abstract

The invention relates to a rotor (1) for an electric traction motor (100). The invention relates to a rotor (1) for a motor vehicle, comprising a hollow shaft (2) for carrying a sheet pack (4) or a winding (5) of the rotor (1), and an engagement (8) arranged at an axial end of the hollow shaft (2). Improved cooling and simplified production are achieved in that a cover (10) different from the hollow shaft (2) closes the hollow shaft (2) and has a radially outwardly open outlet opening (11). The invention further relates to an electric traction motor (100) having such a rotor (1) and to a vehicle (200) having such an electric traction motor (100).

Description

Technical Field

[0001] The invention relates to a rotor for an electric traction motor, which has a hollow shaft which rotates during operation. The invention also relates to an electric traction motor having such a rotor and a vehicle having such an electric traction motor. Background Art

[0002] In an electric traction motor, a rotor and a stator work together. During operation, the rotor rotates about an axis of rotation. This rotation is used to transmit torque for traction.

[0003] Such a traction motor is known, for example, from DE 10 2015 205 724 A1. The rotor of the traction motor has a hollow shaft, which bears a plate set. A toothing for torque transmission is arranged at the axial end of the hollow shaft. On the side of the hollow shaft facing away from the toothing in the axial direction, a pipe axially penetrates into the hollow shaft in order to introduce a cooling medium into the hollow shaft. Summary of the invention

[0004] The invention is based on the object of specifying an improved or at least alternative embodiment for a rotor of a traction motor of the type mentioned at the outset and for such a traction motor and for a vehicle having such a traction motor. In particular, the invention is based on the object of specifying an embodiment for the rotor and for the traction motor and for the vehicle that is distinguished by improved cooling and / or simplified production.

[0005] The invention is therefore based on the basic idea that a separate cover is used adjacent to the toothing for torque transmission in the rotor, which, by means of lateral openings, leads to the targeted introduction of a cooling medium into the hollow shaft of the rotor. The controlled flow of the cooling medium thus achieved, in particular the flow towards the wall of the hollow shaft, leads to improved cooling of the hollow shaft and therefore of the rotor and therefore of the entire traction motor. In addition, the separate configuration of the cover allows the hollow shaft and / or the toothing to be manufactured independently of the cover and subsequently installed. This allows a simplified and particularly universally applicable manufacture of the rotor, in particular the hollow shaft and / or the toothing. Thus, for example, the hollow shaft and / or the toothing can be manufactured in a simple manner by cutting or by forming without taking into account the cover (because the cover has not yet been assembled at this point in time). Therefore, the cover itself can be manufactured in a simple and cost-effective manner.

[0006] According to the present invention, the rotor has a hollow shaft. The hollow shaft rotates around an axial axis during operation and is used to carry the rotor's sheet group and / or winding. In the region of the axial end of the hollow shaft, the rotor has a meshing portion that is rotationally fixed to the hollow shaft. The meshing portion is used to transmit torque. The rotor has a connecting structure in the region of the axial end, and a cover different from the hollow shaft is mounted on the connecting structure. The cover closes the hollow shaft and has at least one opening that is radially open to the outside, so that the flow path of the cooling medium passes through the at least one opening from the radial inside of the cover to the radial outside of the cover and into the hollow shaft. The at least one opening is also referred to as a discharge opening hereinafter.

[0007] The directions described in the present case relate to the axial rotation axis. Thus, "axial" extends parallel to the rotation axis, in particular coaxially. Furthermore, "radial" extends transversely to the rotation axis and thus transversely to the axial direction. Furthermore, the circumferential direction extends around the rotation axis.

[0008] That is, the at least one outlet opening can be used as a nozzle for the cooling medium, in particular independently of its cross section and / or the pressure in the cooling medium. This results in a further improved cooling.

[0009] The toothing and / or the connecting structure can be a component of the hollow shaft. That is to say, the hollow shaft can have the toothing and / or the connecting structure.

[0010] In an advantageous embodiment, the rotor has an axially outwardly protruding and hollow projection at the axial end of the hollow shaft, which projection is rotationally fixed to the hollow shaft and is different from the cover. Therefore, the projection has a reduced inner diameter. Preferably, the projection has a toothing. In addition, preferably, the projection has a connecting structure. Preferably, the projection has a connecting structure axially inside. Therefore, not only the torque transmission but also the connection of the cover takes place in a radially reduced area. In this way, not only the mechanical load in the area of ​​the toothing is reduced, but also the manufacture of the rotor is simplified.

[0011] Advantageously, the toothing is arranged offset from the axial outer side of the projection axially inwards, ie towards the hollow shaft.

[0012] In the present case, a cover different from the hollow shaft means that the cover and the hollow shaft are two-piece. Here, as mentioned above, the cover is mounted on the hollow shaft by means of a connecting structure. The corresponding content applies to the projection different from the cover.

[0013] In principle, the projection can be spaced apart from the hollow shaft in the axial direction. In particular, the projection can be distinct from the shaft.

[0014] In a preferred embodiment, the projection is directly connected to the hollow shaft in a rotationally fixed manner, preferably directly adjoining the hollow shaft in the axial direction. This results in a compact design and improved torque transmission in the rotor. In particular, the projection can be a component of the hollow shaft.

[0015] As mentioned above, the flow path leads from the radial inner side of the cover via at least one outlet opening to the radial outer side of the cover and into the hollow shaft. Suitably, the flow path leads into the rotor at a distance from the cover in the axial direction. For example, the flow path can lead into a hollow projection and then into the hollow shaft via at least one outlet opening. The projection is configured accordingly.

[0016] The toothing can be arranged radially outside or radially inside the hollow shaft or the projection.

[0017] Preferably, the hollow shaft has at least one opening, through which the flow path flows out of the hollow shaft. This opening is also referred to as the shaft opening below. That is, the cooling medium can flow out of the hollow shaft via the at least one shaft opening.

[0018] The rotor is used in an electric traction motor.

[0019] In addition, the traction motor has a stator. The stator and the rotor cooperate during operation so that the rotor rotates around the axis of rotation. Here, the flow path of the cooling medium leads into the hollow shaft via the projection and the cover.

[0020] Preferably, the cooling medium flows in a circuit in which it is cooled, in particular via a heat exchanger. That is, the cooling medium circulates in the circuit during operation.

[0021] Preferably, the traction motor is used in a vehicle in order to drive the vehicle. Here, the rotor is connected to at least one wheel of the vehicle in terms of driving.

[0022] In a preferred embodiment, the projection has a connecting piece pointing axially inwards, which has a connecting structure. This leads to a simplified mounting of the cover on the connecting structure. Thus, manufacturing is simplified in this way.

[0023] Preferably, the connecting piece penetrates into the hollow shaft in the axial direction. This results in a simplified introduction of the cooling medium into the hollow shaft and thus in improved cooling.

[0024] The cover can be installed on the connecting structure in any manner. Here, the cover is suitably connected to the connecting structure in a rotationally fixed manner and is therefore connected to the hollow shaft, in particular to the projection.

[0025] In a preferred embodiment, the cover is mounted on the connecting structure by means of compression. That is to say, the cover and the connecting structure form a compression connection. The compression connection is established by axial plugging. Therefore, in addition to the mechanically stable connection of the cover on the connecting structure, it also leads to simplified production.

[0026] It is conceivable that the cover is pressed onto the connecting structure, in particular onto the connecting pipe. That is, here, the cover surrounds the connecting structure, in particular the connecting pipe, radially on the outside.

[0027] It is conceivable to press the cap into the hollow shaft, for example into the projection, in particular into the connection piece. That is, in this case, the connecting structure surrounds the cap radially on the outside.

[0028] In this case, the cap can protrude axially from the projection and have at least one outlet opening in this region.

[0029] Alternatively or in addition to the compression connection, the cover can be connected to the connecting structure in a material-locking manner. In particular, the cover and the connecting structure can form an adhesive connection.

[0030] In principle, the cover can have a single outlet opening. In this case, the outlet opening preferably extends at least at a right angle, ie at least at 90°, in the circumferential direction.

[0031] Advantageously, the cover has at least two outlet openings which are spaced apart from one another in the circumferential direction, thereby resulting in a uniform flow of the cooling medium into the cavity and thus in a more uniform, improved cooling of the hollow shaft.

[0032] In principle, the cover can be produced in any desired manner.

[0033] For example, the cover may be an injection-moulded component.

[0034] In a preferred embodiment, the cover is designed as a sheet metal formed part, ie is produced by means of sheet metal forming. This results in a cost-effective and weight-reducing way of producing the cover.

[0035] If the cover is manufactured as a sheet metal formed part, the at least one outlet opening can be punched into the sheet metal formed part. That is to say, the at least one opening can be a punched opening.

[0036] It should be understood that, in addition to the rotor, an electric traction motor having a rotor and a vehicle having an electric traction motor, respectively, also belong to the scope of the present invention.

[0037] Further important features and advantages of the invention emerge from the drawings and the associated description of the figures based on the drawings.

[0038] It is self-evident that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar components or components having the same function.

[0040] The accompanying drawings schematically show:

[0041] Figure 1 shows a greatly simplified cross section of an electric machine with a rotor,

[0042] Figure 2 A cross-sectional view of the rotor is shown,

[0043] Figure 3 A cross-sectional view showing a rotor in another embodiment,

[0044] Figure 4 shows a sectional view of a rotor in a further embodiment,

[0045] Figure 5 A cross-sectional view of a rotor in another embodiment is shown. DETAILED DESCRIPTION

[0046] like Figures 1 to 4 The rotor 1 shown as an example is used in an electric traction motor 100. Figure 1 exemplarily and greatly simplified. Figure 1 As shown, the traction motor 100 can be used to drive the vehicle 200. For this purpose, as shown in FIG. Figure 1 As shown, the traction motor 100 is connected to at least one wheel 201 of a vehicle 200 in terms of drive. The traction motor 100 also has a stator 101. During operation, the stator 101 and the rotor 1 interact electromagnetically so that the rotor 1 rotates about an axial axis of rotation R.

[0047] The directions described in the present case relate to the axial rotational axis R. In this case, “axial” extends parallel to, in particular coaxially to, the rotational axis R. Furthermore, “radial” extends transversely to the rotational axis R and thus transversely to the axial direction. Furthermore, a circumferential direction U extends around the rotational axis R.

[0048] according to Figures 2 to 5The rotor 1 has a hollow shaft 2. The hollow shaft 2 extends axially and in the circumferential direction U and delimits a cavity 3 on the inside, which cavity is also referred to as the shaft cavity 3 in the following text. The hollow shaft 2 carries radially on the outside a lamination pack 4 and / or at least one winding 5 of the rotor 1, which lamination pack and the winding are only connected to each other. Figure 1 Indicated in the Figures 2 to 5 As is known, the rotor 1 has a toothing 8 at the axial end of the hollow shaft 2. The toothing 8 is used for torque transmission and is therefore rotationally fixed to the hollow shaft 2. In other words, a drive connection to the wheel 201 can be achieved by means of the toothing 8. The toothing 8 can be as follows Figures 2 to 4 As shown, it is arranged radially inside, or as Figure 5 The arrangement shown is radially external.

[0049] If you can Figures 2 to 4 As is known, an axially outwardly protruding projection 6 can be arranged at the axial end of the hollow shaft 3, which projection is rotationally fixed to the hollow shaft 3. In the embodiment shown, the projection 6 directly adjoins the hollow shaft 2 in the axial direction. The projection 6 is hollow in design, i.e. radially delimits a cavity 7 on the outside, which is also referred to as the projection cavity 7 below. Here, the projection 6 has a toothing 8. That is, by means of the projection 6, a diameter reduction relative to the hollow shaft 2 is achieved at the axial end, wherein the toothing 8 is arranged in the region of this reduction.

[0050] If you can Figure 5 As is known, the toothing 8 can also be arranged directly on the hollow shaft 2 and in particular formed. Figure 5 In the embodiment shown, the rotor 1 has no such projections 6 and therefore has an at least substantially constant diameter.

[0051] If you can Figures 2 to 5 As is known, the hollow shaft 2 has a structure 9 in the region of the axial end, by means of which the cap 10 is mounted on the projection 6. This structure 9 is also referred to as the connecting structure 9 below. Figures 2 to 4 In the embodiment of FIG. 1 , the protrusion 6 has a connecting structure 9 in the axial direction. Figures 2 to 5 As shown, the cover 10 is distinct from the hollow shaft 2 and from the projection 6. The cover 10 closes the hollow shaft 2. Figures 2 to 4 In the embodiment of FIG. 1 , the cover 10 closes the projection 6. That is, the cover 10 separates the projection cavity 7 from the shaft cavity 3, which is connected to the shaft cavity 3 without the cover 10. Figure 5 In the embodiment of the present invention, the cover 10 divides the shaft cavity 3 in the region of the axial end or the toothing 8. In this case, the cover 10 has at least one opening 11 which is open radially outwards and which establishes a fluid connection between the projection cavity 7 and the shaft cavity 3. Therefore, the cooling medium can only be supplied in the region of the toothing 8. Figure 2 and5 The flow path 12 indicated in FIG. 1 leads from the radial inner side 13 of the cover 10 through at least one opening 11 to the radial outer side 14 of the cover 10 and into the hollow shaft 2, i.e. into the shaft cavity 3. The at least one opening 11 is also referred to as the outlet opening 11 below. Figures 2 to 4 In the exemplary embodiment of FIG. 1 , the flow path 12 opens into the hollow shaft 2 via the projection 6 and via the cap 10 . Figure 5 In the embodiment of the invention, the flow path 12 opens into the hollow shaft 2 via the axial end and via the cover 10. Thus, the cooling medium can be introduced into the hollow shaft 2 in a targeted manner, so that the cooling of the hollow shaft 2 and thus the cooling of the rotor 1 and thus the cooling of the traction motor 100 is improved. In addition, the cover 10, which is different from the hollow shaft 2 and the projection 6, allows the cover 10 to be installed after the hollow shaft 2 and the projection 6, in particular the toothing 8, are manufactured. Thus, a simplified manufacture of the rotor 1 is achieved. In addition, by Figures 2 to 5 As can be seen from the comparison, the toothing 8 and in particular also the projection 6 can be produced in a simplified manner in different sizes and geometries.

[0052] The cap 10 can be designed as a sheet metal molded part 16 . This leads to a further simplified and cost-effective production. In this case, the outlet opening 11 can be produced in the sheet metal molded part 16 by means of stamping.

[0053] like Figures 2 to 5 As shown, the cover 10 has at least two outlet openings 11 in the embodiment shown, which are spaced apart from one another in the circumferential direction U. Figures 2 to 4 As is known, the hollow shaft 2 in the illustrated embodiment has openings 15 spaced apart from one another in the circumferential direction U, which are used to discharge the cooling medium from the hollow shaft 2, and which are also referred to below as shaft openings 15. In the illustrated embodiment, the shaft openings 15 are arranged purely by way of example in the region of the cover 10 and are spaced apart radially from the outlet openings 11. That is, the flow path 12 leads out of the shaft cavity 3 through the shaft openings 15.

[0054] exist Figure 2 and 3 In the embodiment shown, the connecting structure 9 is a component of a connecting piece 16 of the projection 6. That is, the projection 6 has a connecting piece 17 with the connecting structure 9. The connecting piece 17 here points axially inwards and protrudes axially into the hollow shaft 2, that is, into the shaft cavity 3.

[0055] In the exemplary embodiment shown, the cap 10 is mounted on the hollow shaft 2 or on the projection 6 by means of compression. This means that the cap 10 and the connecting structure 9 form a compression connection 18.

[0056] like Figure 2 and 3As shown in the embodiment of FIG. 1 , the cover 10 can be pressed onto the connecting pipe 17 , that is, it can surround the connecting pipe 17 radially on the outside. That is, the connecting structure 9 is arranged radially outside the connecting pipe 17 .

[0057] Alternatively, if Figure 4 and 5 As shown in the embodiment, the cover 10 can be pressed into the protrusion 6 or pressed into the hollow shaft 2, that is, the protrusion 6 ( Figure 4 ) or hollow shaft 2( Figure 5 ) can surround the cover 10 radially on the outside. In this case, the connecting structure 9 is arranged on the protrusion 6 ( Figure 4 ) or hollow shaft 2( Figure 5 ). Figure 4 In the illustrated embodiment, the cap 10 protrudes from the projection 6 in the axial direction and into the hollow shaft 2 , and has an outlet opening 11 outside the projection 6 .

Claims

1. A rotor (1) for an electric traction motor (100), The rotor has a hollow shaft (2) for carrying a lamination package (4) and / or a winding (5) of the rotor (1), wherein the hollow shaft rotates about an axial rotation axis (R) during operation. in, The rotor (1) has a toothing (8) in the region of an axial end of the hollow shaft (2) for transmitting torque. The rotor (1) has a connecting structure (9) in the region of the axial end, a cover (10) different from the hollow shaft (2) is mounted on the connecting structure, The cover (10) closes the hollow shaft (2) and has at least one outlet opening (11) which is open radially outward, so that a flow path (12) of a cooling medium leads from a radial inner side (13) of the cover (10) through the at least one outlet opening (11) to a radial outer side (14) of the cover (10) and into the hollow shaft (2).

2. The rotor according to claim 1, It is characterized in that The rotor (1) has a projection (6) protruding axially outward on the axial end of the hollow shaft (2), the projection having the toothing (8), and the projection being hollow. The protrusion (6) is different from the cover (10) and has the connection structure (9) axially inside.

3. The rotor according to claim 2, It is characterized in that The projection (6) has a connecting piece (17) pointing axially inwards and having the connecting structure (9).

4. The rotor according to claim 3, It is characterized in that The connecting piece (17) extends axially into the hollow shaft (2).

5. A rotor according to any one of claims 1 to 3, It is characterized in that The cover (10) forms a press-fit connection (18) together with the connection structure (9).

6. A rotor according to claim 5 and claim 3 or 4, It is characterized in that The cap (10) is pressed onto the connecting piece (17).

7. The rotor according to claim 5, It is characterized in that The cover (10) is pressed into the projection (6).

8. A rotor according to any one of claims 1 to 7, It is characterized in that The cover (10) has at least two discharge openings (11) which are spaced apart from each other in a circumferential direction (U).

9. A rotor according to any one of claims 1 to 8, It is characterized in that The cover (10) is designed as a formed sheet metal part (16).

10. An electric traction motor (100), in particular for use in a vehicle (200), The electric traction motor has a rotor (1) according to any one of claims 1 to 9 and a stator (101), wherein: The rotor (1) and the stator (101) interact in such a way during operation that the rotor (1) rotates about the rotation axis (R). The flow path (12) of the cooling medium leads into the hollow shaft (2) via the cover (10).

11. A vehicle (100) having an electric traction motor (100) according to claim 10.

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