Component of an electric drive motor of a motor vehicle

Abstract

Proposed is an assembly (1) of an electric drive motor of a motor vehicle, comprising a rotor shaft (2), a slip ring assembly (3) on the rotor shaft, and a brush module (4) encompassing the slip ring assembly (3), the brush module (4) having a central support plate (21), on each of its bottom sides (5, 6) a brush support plate (7) with at least one brush (8, 9) is applied, wherein the at least one brush (8, 9) on each bottom side (5, 6) is in sliding contact with a current collection ring (10, 11) of the slip ring assembly (3), which current collection rings (10, 11) lie on a cylindrical surface (12) of a support ring (14) joined to an outer shell (13) of the rotor shaft (2) as part of the slip ring assembly (3), wherein a supply channel (16) for oil runs longitudinally through the rotor shaft (2) for cooling a brush current collection ring contact (15), which in the case of the slip ring assembly (3) a transverse channel (17) in the rotor shaft (2) is cut,which is connected to a drainage channel (18) through the support ring (14), wherein an opening (19) of the respective drainage channel (18) is located on the outer surface (12) of the support ring (14) between the two current collection rings (10, 11).

Description

The invention relates to an assembly of an electric drive machine of a motor vehicle, having a rotor shaft, a slip ring unit on the rotor shaft and a brush module which comprises the slip ring unit and has a central support plate, on each of the base sides of which a brush support plate with in each case at least one current-conducting brush is applied at least indirectly, wherein the at least one brush is in sliding contact per base side with a current take-off ring of the slip ring unit, which current take-off rings are located on a lateral surface of a support ring joined to an outer jacket of the rotor shaft as a constituent part of the slip ring unit, and wherein a cooling of a brush current take-off ring contact with oil is provided.An assembly with an oil-cooled brush current take-off ring contact (keyword: active cooling) is disclosed in DE 10 2021 122 065 B3. It can be seen, for example, in FIG. 4 a channel for cooling oil running through the support plate in the direction of its inner edge. The channel opens out in front of the inner edge of the support plate at one of its end faces.It is an object to provide a brush module with optimized cooling of its brush current collector ring contact.According to the invention, this object is achieved in that, for cooling the brush current collector ring contact with oil, a feed duct for the oil runs longitudinally through the rotor shaft, which feed duct is cut in the slip ring unit by at least one transverse duct for the oil in the rotor shaft, which duct is connected to at least one discharge duct for the oil by the carrier ring, wherein an opening of the respective discharge duct is situated on the lateral surface of the carrier ring between the two current collector rings.Thus, at least one transverse and discharge channel which is in fluid communication with the feed channel by the rotor shaft is proposed. Both channels (transverse and discharge channel) are preferably aligned with one another, wherein according to a dependent claim an annular groove removal is also possible, so that this alignment is not absolutely necessary, which helps to save assembly costs.The cooling oil thus reaches the contact of the respective brush on the current take-off ring in a very targeted and dosed manner under pressure. A simple variant provides here for the at least one discharge channel to be arranged through the support ring centrally between the current collector rings and to be directed onto an inner edge of the support plate.According to an expedient concretization of the invention, the aforementioned inner edge of the supporting plate is beveled in a roof-like manner for more targeted oil supply in the circumferential region of the respective brush on each side and thus forms a baffle surface. Separate guide elements joined to the support plate are also conceivable and provided.It is also proposed to assign each brush support plate side at least one discharge channel for a targeted supply of cooling oil. The respective channel can extend, for example, obliquely through the rotor shaft and the support ring towards the respective contact region. Alternatively, it is provided to apply two channel groups (one per brush support plate side) which are arranged one behind the other in the axial direction of the rotor shaft.Preferably, each brush support plate carries a plurality of circumferentially evenly distributed brushes, for example. 3. it is proposed to associate each brush with a drain channel or a transverse channel in alignment with a drain channel, which results in a fanned distribution for excellent oil cooling. In the first-mentioned variant, it is conceivable, for example, to provide only one transverse channel in the rotor shaft, from which channel the cooling oil is guided into the respective discharge channels via an annular groove distribution (outer jacket rotor shaft / bore support ring).The cooling oil can be directed into the rotor shaft at one of the end faces thereof. However, a cooling oil inlet into the rotor shaft via its outer jacket is also conceivable and provided equally. In addition, the mouth of the respective discharge channel can have a tapered / nozzle-like configuration. Instead of oil such as lubricating oil / motor oil for cooling the above-described contact, another medium may also be selected.For the drawing:• Figure 1 shows a longitudinal half-section through the assembly in an axially front portion of the rotor shaft;• FIG. 2 shows a detail of the sectional view as mentioned above with a transverse and discharge channel running obliquely;• FIG. 3 again shows a detail of the sectional view with an annular groove tap for the cooling oil, and• Fig. 4 shows a cross-section through the rotor shaft and the slip ring unit in the longitudinal portion of the support plate.FIG. 1 shows a longitudinal half section of an assembly 1 of an electric drive machine (externally excited synchronous motor) of a motor vehicle. An axial end piece of a rotor shaft 2, a slip ring unit 3 thereon and a brush module 4 comprising the slip ring unit 3 are shown.The brush module 4 mentioned above has a central support plate 21, and the brush support plate side 23 of the brush module 4 shown on the left of the support plate 21 in FIG. 1 has a brush support plate 7 awith three current-conducting brushes 8 distributed over the circumference. The brush support plate side 24 of the brush module 4 shown on the right of the support plate 21 in FIG. 1 has a brush support plate 7 bhaving three current-conducting brushes 9 distributed over the circumference. Each brush 8, 9 is acted upon radially inward via a brush spring 28, 29 designed as a torsion leg spring onto a respective current take-off ring 10, 11 on a lateral surface 12 of a support ring 14 of the slip ring unit 3. The brushes 8, 9 are in sliding contact with their respective current-collecting rings 10, 11.A respective brush current collector ring contact 15, i.e. a region of sliding contact of the respective brush 8, 9 on the corresponding current collector ring 10, 11, is actively oil-cooled for good heat dissipation.Running longitudinally through the rotor shaft 2 is a feed duct 16 for cooling oil, which is directed under pressure from the direction of the electric drive machine (see arrow indication). In the case of the slip ring unit 3, seen in the longitudinal direction, centrally between the current collector rings 10, 11, the feed duct 16 is cut by 6 circumferentially distributed transverse ducts 17 for the purpose of conveying the cooling oil.As can be seen in this context from FIG. 4, in a rotational position of the rotor shaft 2, a respective transverse channel 17 with a respective aligned discharge channel 18 in the support ring 14 of the slip ring unit 3 has exactly one brush 8, 9. The three circumferentially distributed (rear) brushes 9 of the brush support plate 7 bon the brush support plate side 24 can be seen in FIG. 4.According to FIGS. 1, 2, an opening 19 (the outlet) of the respective discharge channel 18 lies on the circumferential surface 12 of the support ring 14 between the two current draw rings 10, 11 thereof. according to FIG. 1, this opening 19 is placed exactly centrally and is directed onto an inner edge 20 of the support plate 21 of the brush module 4. The inner edge 20 is formed in the circumferential section of the respective brush 8, 9 (one of the brushes 9 can be seen here) as a beveled baffle surface 22. The latter serves to redirect the oil exiting the discharge channel 18 in the direction of the respective brush current collector ring contact 15.According to the variant according to FIG. 2, a transverse and a drain channel 17, 18 aligned with it run obliquely through the rotor shaft 2 and the support ring 14 for each brush 8, 9 and are directed toward the brush current collector ring contact 15 of the respective brush support plate side 23, 24. A channel group is visible here, consisting of a transverse channel and a discharge channel 17, 18 directed toward the brush support plate side 24, which is shown here on the right.According to FIG. 3, an outlet region 25 of a transverse channel 17 in the rotor shaft 2 terminates in an annular groove 27 in its outer jacket 13, and the support ring 14 again has the aforementioned circumferentially distributed discharge channels 18, which are fed by the cooling oil circulating in the annular groove 27. Thus, a rotationally oriented joining of the support ring 14 on the rotor shaft 2 is superfluous. It is clear that instead of exactly one transverse channel 17 a plurality of transverse channels 17 can also be present in the rotor shaft 2.List of Reference Numbers1 Assembly 2 Rotor shaft 3 Slip ring unit 4 Brush module 5 Base side 6 Base side 7 a Bürsten support plate 7 b Bürsten support plate 8 Brush 9 Brush 10 Current draw ring 11 Current draw ring 12 Lateral surface 13 Outer jacket 14 Support ring 15 Brush current draw ring contact 16 Feed channel 17 Transverse channel 18 Discharge channel 19 Opening 20 Inner edge 21 Support plate 22 Baffle surface 23 Brush support plate side 24 Brush support plate side 25 Outlet region 26 Inlet region 27 Annular groove 28 Brush spring 29 Brush springReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 122 065 B3

[0002]

Claims

Assembly (1) of an electric drive machine of a motor vehicle, having a rotor shaft (2), a slip ring unit (3) on the rotor shaft (2) and a brush module (4) which comprises the slip ring unit (3) and has a central support plate (21), on each of the base sides (5, 6) of which a brush support plate (7a, 7b) with in each case at least one current-conducting brush (8, 9) is applied at least indirectly, wherein the at least one brush (8, 9) per base side (5, 6) is in sliding contact with a current-take-off ring (10, 11) of the slip ring unit (3), which current-take-off rings (10, 11) are located on a lateral surface (12) of a support ring (14) joined to an outer shell (13) of the rotor shaft (2) as a constituent part of the slip ring unit (3), wherein, for cooling a brush current take-off ring contact (15), a feed channel (16) for oil runs longitudinally through the rotor shaft (2), which feed channel is cut in the case of the slip ring unit (3) by at least one transverse channel (17) for the oil in the rotor shaft (2), which transverse channel is connected to at least one discharge channel (18) for the oil by the support ring (14), and wherein an opening (19) of the respective discharge channel (18) on the lateral surface (12) of the support ring (14) lies between the two current take-off rings (10, 11).Assembly according to claim 1, wherein said at least one drain channel (18) passes radially through said support ring (14), is placed at a middle between its current collector rings (10, 11) and is directed towards an inner edge (20) of said support plate (21) of said brush module (4).Assembly according to claim 1 or 2, wherein an inner edge (20) of the support plate (21) of the brush module (4) is present in the peripheral portion of the respective brush (8, 9) as a beveled baffle (22) for diverting the oil exiting from the discharge channel (18) in the direction of the respective brush current take-off ring contact (15).Assembly according to claim 1, wherein for each brush support plate side (23, 24) of the brush module (4) at least one drain channel (18) is provided, which drain channel (18) leads obliquely through the support ring (14) and is directed towards the brush current take-off ring contact (15) of the respective brush support plate side (23, 24).Assembly according to claim 1, wherein an outlet region (25) of the at least one transverse channel (17) in the rotor shaft (2) and / or an inlet region (26) of the discharge channel (18) in the support ring (14) lie in an annular groove (27).Assembly according to claim 1 or 5, wherein a plurality of circumferentially distributed transverse channels (17) are provided in the rotor shaft (2) and / or a plurality of circumferentially distributed discharge channels (18) are provided in the support ring (14), wherein in the case of a plurality of transverse and discharge channels (17, 18) being present, in each case one transverse channel (17) is aligned with a discharge channel (18).

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