Electric Machine and Motor Vehicle

Abstract

An electric machine has a stator, a rotor, and a slip ring module which is connected to a motor shaft of the electric machine. The slip ring module is equipped with at least one wire guiding channel, through which a respective contact wire is guided in order to electrically connect a rotor winding to a slip ring. A first section of the wire guiding channel runs from the slip ring in the axial direction parallel to the motor shaft. A second section of the wire guiding channel runs adjacently thereto radially outwards. An elastic seal element which surrounds the respective contact wire is arranged in or on the second section in order to seal the wire guiding channel to prevent a lubricant from entering the channel.

Claims

1.-10. (canceled)

11. An electric machine comprising: a stator; a rotor which is mounted to be rotatably movable about a center longitudinal axis of a motor shaft of the electric machine; and a slip ring module which is connected to the motor shaft, is fixed in terms of rotation with respect to the rotor, is rotatable relative to a slip ring of the electric machine, and has a wire guiding channel through which a contact wire for electrically connecting a rotor winding to the slip ring is guided from the latter as far as a wire outlet of the slip ring module, wherein: a first section of the wire guiding channel runs from the slip ring in an axial direction parallel to a center longitudinal axis and an adjoining second section of the wire guiding channel runs radially outward as far as the wire outlet, and an elastic sealing element surrounding the contact wire for sealing the wire guiding channel from penetration of a lubricant at the wire outlet is arranged in or on the second section.

12. The electric machine according to claim 11, wherein: the wire guiding channel is mostly filled with a thermoset molding compound surrounding the contact wire.

13. The electric machine according to claim 11, wherein: the sealing element is manufactured from an elastomer having a dielectric strength of at least 15 kV/mm.

14. The electric machine according to claim 11, wherein: the elastomer is an ethylene acrylate elastomer.

15. The electric machine according to claim 11, wherein: the sealing element is configured as a sealing plug which is arranged in the second section of the wire guiding channel.

16. The electric machine according to claim 15, wherein: the sealing plug projects radially outward beyond an end, formed by the wire outlet, of the second section of the wire guiding channel.

17. The electric machine according to claim 15, wherein: the sealing plug has an at least substantially mushroom-shaped form with a shaft region and a head region which is widened in comparison to the shaft region, and a largest diameter of the head region is larger than a smallest diameter of the second section of the wire guiding channel.

18. The electric machine according to claim 15, wherein: the sealing plug is fixed in the second section by a molding compound which encases and fixes the contact wire at least in the first section.

19. The electric machine according to claim 18, wherein: the sealing plug has a constriction with a reduced diameter.

20. The electric machine according to claim 19, wherein: a widened portion of the sealing plug delimiting the constriction on a side facing the center longitudinal axis is interrupted in regions in a circumferential direction of the sealing plug.

21. A motor vehicle comprising the electric machine according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows a schematic sectioned perspective view of part of an electric

[0023] machine.

[0024] FIG. 2 shows a schematic perspective view of a sealing plug for a wire guiding channel of the electric machine.

[0025] FIG. 3 shows a partial schematic sectional view of a region around the sealing plug in an unfilled state.

[0026] FIG. 4 shows a partial schematic sectional view of a region around the sealing plug in a filled state.

[0027] FIG. 5 shows a partial schematic sectional view of a region with an alternative sealing element.

DETAILED DESCRIPTION OF THE DRAWINGS

[0028] In the figures, identical and functionally identical elements are in each case provided with the same reference signs.

[0029] FIG. 1 shows a schematic sectioned perspective view of part of an electric machine 10. In particular, part of a slip ring module 12 which can rotate about a center longitudinal axis 14 is illustrated here. The center longitudinal axis 14 runs here longitudinally centrally through a shaft receiving space 16 which is surrounded by the slip ring module 12 and in which a motor shaft of the electric machine 10 can be arranged. A wire guiding channel 18 runs in the slip ring module 12. This wire guiding channel 18 has a first section 20 running in the axial direction parallel to the center longitudinal axis 14 and a second section 22 which adjoins the first section and runs radially through a wall of the slip ring module 12. Furthermore, a slip ring 24 which likewise surrounds the shaft receiving space 16 is illustrated here. A contact wire 26 is arranged here in the wire guiding channel 18, the contact wire electrically contacting the slip ring 24 and, at its other end, being guided out of the wire guiding channel 18 through the second section 22 of the latter. In the complete electric machine 10, that end of the contact wire 26 which is led out of the second section can be guided as far as the rotor winding, i.e. can be electrically connected to such a rotor winding.

[0030] Analogously to the wire guiding channel 18, the contact wire 26 has an axial piece 28 which runs in the first section 20 and therefore likewise offset radially outward parallel to the center longitudinal axis 14. Also analogously to the wire guiding channel 18, a radial piece 30 of the contact wire 26 adjoins this axial piece 28. This radial piece 30 is guided radially outward through the second section 22. An end of the second section 22 lying radially on the outside is referred to here as a wire outlet 32 from which the radial piece 30 of the contact wire 26 therefore projects out of the slip ring module 12.

[0031] In order to better show a course of the contact wire 26, the wire guiding channel 18 is illustrated here in an empty, i.e. unfilled state. Within the scope of further manufacturing of the electric machine 10, the wire guiding channel 18 is also enclosed, i.e. a region surrounding the contact wire 26 is also filled in order to electrically insulate and spatially fix the contact wire 26.

[0032] In the axial direction, i.e. in the direction along the center longitudinal axis 14, sealing rings are arranged here on both sides of the wire outlet 32, namely a first seal 34 on a side facing the slip ring 24 and a second seal 36 on the opposite other side of the wire outlet 32.

[0033] In the present case, the electric machine 10 or the slip ring module 12 can have a plurality of wire guiding channels 18 having a respective dedicated contact wire 26 arranged therein. By way of example, a further wire guiding channel 38 with a further contact wire 40 is illustrated here. The statements and explanations provided here regarding the wire guiding channel 18 and the contact wire 26 or the further wire guiding channel 38 and the further contact wire 40 are to apply analogously to the wire guiding channels or contact wire and to further wire guiding channels or contact wires that are not illustrated here.

[0034] In spite of the seals 34, 36, it has been shown that, during the operation of the electric machine 10, oil can pass to the wire outlet 32 and along the contact wire 26 through the wire guiding channel 18 as far as the slip ring 24 or as far as a slip contact formed by the slip ring 24 and the contact wire 26. In order to avoid this, the wire guiding channel 18 or the second section 22 thereof is sealed here by an additional sealing element, which surrounds the contact wire 26 in the region of the second portion 22 or at the wire outlet 32, in order to prevent or to reduce oil penetrating the wire guiding channel 18.

[0035] Such a sealing element is illustrated in a schematic perspective view in FIG. 2 in the form of a sealing plug 42. The sealing plug 42 here has a substantially mushroom-shaped basic form with a widened head region 44 and an adjoining narrower shaft region. A constriction 46 is provided here on the shaft region. On a side of the constriction 46 opposite the head region 44, the sealing stopper 42 has a plurality of widened portions 48 distributed uniformly in the circumferential direction. These widened portions 48 are interrupted in the circumferential direction by interruptions 50 in each case lying in between. In the region of the interruptions 50, the sealing plug 42 therefore has a smaller diameter than in the region of the widened portions 48.

[0036] During the manufacturing of the electric machine 10, the sealing stopper 42 can be plugged or pushed from the outside inward for example in the radial direction onto the radial piece 30 and into the second section 22. A lower side of the head region 44 facing the constriction 46 can then rest on an outer side of the slip module 12 in the region of the wire outlet 32.

[0037] Here too, for the sake of clarity, the wire guiding channel 18 is still illustrated in an unfilled state, i.e. empty except for the contact wire 26 and the sealing plug 42, during the manufacturing of the electric machine 10.

[0038] FIG. 4 also shows the region around the second section 22 in a likewise partial schematic sectional view. However, the wire guiding channel 18 is illustrated here in a filled state. The wire guiding channel 18 is filled here by a thermoset molding compound 52. This molding compound 52 therefore encloses the contact wire 26 and at least partially the sealing plug 42. In particular, the molding compound 52 fills the second section 22 of the wire guiding channel 18 in the region of the constriction 46 of the inserted sealing plug 42 and therefore fixes not only the contact wire 26 but also the sealing plug 42. By contrast, the shaft receiving space 16 is not filled by the molding compound 52, i.e. remains free in order to receive the motor shaft, not illustrated here, of the electric machine 10. The shaft receiving space 16 can be separated, for example, from the region filled here by the molding compound 52. Similarly, during a manufacturing process, a place holder element corresponding in its shape to the shaft receiving space 16 can be inserted into the slip ring module 12, then encapsulated by injection molding or potted with the molding compound 52 and subsequently, after at least partial solidification or hardening of the molding compound 52, removed again in order to release the shaft receiving space 16.

[0039] FIG. 5 shows a partial schematic sectional view of a region around a radial section of the further wire guiding channel 38 with an alternatively configured sealing element. The sealing element for sealing the further wire guiding channel 38 is designed here as an 0 ring 54 surrounding the further contact wire 40. Depending on the application or requirements, in a specific electric machine 10, all of the sealing elements can preferably be formed identically, i.e. either as a sealing plug 42 or as an O ring 54.

[0040] Overall, the described examples show how wire outlets of wires for electrical contacting of rotor windings or slip contacts on the slip ring module 12 can be sealed by a sealing element, in particular an elastomer sealing plug with a fastening anchor, in order to improve oil tightness and therefore reliability in particular in a wet-running, i.e. oiled, operation of the electric machine 10.

TABLE-US-00001 List of reference signs 10 Electric machine 12 Slip ring module 14 Center longitudinal axis 16 Shaft receiving space 18 Wire guiding channel 20 First section 22 Second section 24 Slip ring 26 Contact wire 28 Axial piece 30 Radial piece 32 Wire outlet 34 First seal 36 Second seal 38 Further wire guiding channel 40 Further contact wire 42 Sealing plug 44 Head region 46 Constriction 48 Widened portions 50 Interruptions 52 Molding compound 54 O ring