Assembly of an electric drive machine of a motor vehicle

Abstract

The invention relates to an assembly (1) of an electric drive machine of a motor vehicle, said assembly comprising: a rotor shaft (2); a slip ring unit (3) on the rotor shaft; and a brush module (4) which encloses the slip ring unit (3) and has a central carrier plate (21), on each of the base sides (5, 6) of which a brush carrier plate (7) is applied, each brush carrier plate having at least one brush (8, 9), wherein the at least one brush (8, 9) on each base side (5, 6) is in sliding contact with a current-collecting ring (10, 11) of the slip ring unit (3), said current-collecting rings (10, 11) being located on a lateral surface (12) of a support ring (14) that is part of the slip ring unit (3) and is joined to an outer casing (13) of the rotor shaft (2), wherein, in order to cool a contact point (15) between the brush and the current-collecting ring, a feed channel (16) for oil runs longitudinally through the rotor shaft (2) and, in the slip ring unit (3), intersects in the rotor shaft (17) with a transverse channel (17) which is connected to a discharge channel (18) passing through the support ring (14), wherein an opening (19) of the discharge channel (18) is located on the lateral surface (12) of the support ring (14) between the two current-collecting rings (10, 11).

Description

[0001] Assembly of an electric drive motor of a motor vehicle

[0002] The invention relates to an assembly of an electric drive machine of a motor vehicle, with a rotor shaft, a slip ring unit on the rotor shaft and a brush module comprising the slip ring unit, which has a central support plate, on each of the bottom sides of which a brush support plate with at least one current-conducting brush is applied at least indirectly, wherein the at least one brush on each bottom side is in sliding contact with a current collection ring of the slip ring unit, which current collection rings are located on a jacket surface of a support ring joined to an outer jacket of the rotor shaft as a component of the slip ring unit and wherein cooling of a brush-current collection ring contact with oil is provided.

[0003] An assembly with an oil-cooled brush current collection ring contact (keyword: active cooling) is disclosed in DE 10 2021 122 065 B3. Figure 4, for example, shows a channel for cooling oil running through the support plate toward its inner edge. The channel opens in front of the inner edge of the support plate at one of its end faces.

[0004] The task is to create a brush module with optimized cooling of its brush current collection ring contact.

[0005] According to the invention, this object is achieved in that, for cooling the brush current collection ring contact with oil, a supply channel for the oil runs longitudinally through the rotor shaft, which in the slip ring unit is intersected by at least one transverse channel for the oil in the rotor shaft, which is connected to at least one discharge channel for the oil through the support ring, wherein an opening of the respective discharge channel is located on the outer surface of the support ring between the two current collection rings.

[0006] Thus, at least one transverse and discharge channel is proposed, which is fluidly connected to the supply channel through the rotor shaft. Both channels (transverse and discharge channels) are preferably aligned with each other. According to a subclaim, an annular groove removal is also possible, so that this alignment is not absolutely necessary, which helps to save assembly costs.

[0007] The cooling oil thus reaches the contact of the respective brush on the current collection ring in a very targeted and metered manner, with pressure applied. A simple variant provides for at least one discharge channel to be arranged through the support ring centrally between the current collection rings and directed toward an inner edge of the support plate.

[0008] According to a practical embodiment of the invention, the aforementioned inner edge of the support plate is beveled in a roof-like manner on each side for more targeted oil supply in the peripheral area of ​​the respective brush, thus forming a deflection surface. Separate guide elements joined to the support plate are also conceivable and intended.

[0009] It is also proposed to assign at least one discharge channel to each side of the brush support plate for a targeted supply of cooling oil. The respective channel can, for example, run diagonally through the rotor shaft and the support ring, directed toward the respective contact area. Alternatively, it is proposed to apply two groups of channels arranged one behind the other in the axial direction of the rotor shaft (one per side of the brush support plate).

[0010] Preferably, each brush support plate carries several brushes evenly distributed around the circumference, for example, three. It is proposed to assign each brush a discharge channel or a transverse channel aligned with a discharge channel, resulting in a fanned-out distribution for excellent oil cooling. In the first variant, it is conceivable, for example, to provide only one transverse channel in the rotor shaft, from which the cooling oil is guided into the respective discharge channels via an annular groove distribution (outer casing of the rotor shaft / bore of the support ring).

[0011] The cooling oil can be fed into the rotor shaft at one of its end faces.

[0012] However, it is also conceivable and intended that cooling oil enter the rotor shaft via its outer casing. Furthermore, the opening of the respective discharge channel can have a tapered / nozzle-like design. Instead of oil, such as lubricating oil or engine oil, another medium can also be chosen to cool the aforementioned contact.

[0013] About the drawing:

[0014] • Figure 1 shows a longitudinal half-section through the assembly in an axially forward section of the rotor shaft;

[0015] • Figure 2 shows a section of the sectional view as mentioned above with diagonally running cross and drainage channels;

[0016] • Figure 3 again shows a section of the sectional view with annular groove tap for the cooling oil and

[0017] • Figure 4 shows a cross section through the rotor shaft and the slip ring unit in the length section of the support plate.

[0018] Figure 1 shows a longitudinal section of an assembly 1 of an electric drive unit (separately excited synchronous motor) of a motor vehicle. It shows an axial end piece of a rotor shaft 2, a slip ring unit 3 mounted thereon, and a brush module 4 comprising the slip ring unit 3.

[0019] The aforementioned brush module 4 has a central support plate 21. The brush support plate side 23 of the brush module 4, shown to the left of the support plate 21 in Figure 1, has a brush support plate 7a with three circumferentially distributed, current-conducting brushes 8. The brush support plate side 24 of the brush module 4, shown to the right of the support plate 21 in Figure 1, has a brush support plate 7b with three circumferentially distributed, current-conducting brushes 9. Each brush 8, 9 is acted upon radially inwardly by a brush spring 28, 29 designed as a torsion spring onto a respective current collection 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 collection rings 10, 11. A respective brush-current collection ring contact 15, ie a region of a sliding contact of the respective brush 8, 9 on the corresponding current collection ring 10, 11, is actively oil-cooled for good heat dissipation.

[0020] A supply channel 16 for cooling oil runs longitudinally through the rotor shaft 2, which is supplied under pressure from the direction of the electric drive motor (see arrow). In the slip ring unit 3, located centrally between the current collection rings 10, 11 in the longitudinal direction, the supply channel 16 is intersected by six circumferentially distributed transverse channels 17 for the further transmission of the cooling oil.

[0021] As can be seen in this context from Figure 4, in a rotational position of the rotor shaft 2, each transverse channel 17 with a respective discharge channel 18 aligned therewith in the support ring 14 of the slip ring unit 3 points to exactly one brush 8, 9. The support ring 14 is fixed in a rotationally oriented manner on the rotor shaft 2. Figure 4 shows the three circumferentially distributed (rear) brushes 9 of the brush support plate 7b on the brush support plate side 24.

[0022] According to Figures 1 and 2, an opening 19 (the outlet) of the respective discharge channel 18 is located on the outer surface 12 of the support ring 14 between its two current collection rings 10, 11. According to Figure 1, this opening 19 is positioned exactly centrally and directed toward an inner edge 20 of the support plate 21 of the brush module 4. The inner edge 20 is formed as a beveled baffle surface 22 in the peripheral section of the respective brush 8, 9 (one of the brushes 9 is visible here). The latter serves to redirect the oil escaping from the discharge channel 18 toward the respective brush-current collection ring contact 15.

[0023] According to the variant shown in Figure 2, for each brush 8, 9, a transverse channel and an aligned discharge channel 17, 18 run diagonally through the rotor shaft 2 and the support ring 14 and are directed toward the brush current collection ring contact 15 of the respective brush support plate side 23, 24. This shows a channel group consisting of a transverse channel and a discharge channel 17, 18, directed toward the brush support plate side 24 shown here on the right.

[0024] According to Figure 3, an outlet region 25 of a transverse channel 17 in the rotor shaft 2 ends in an annular groove 27 in its outer casing 13. The support ring 14, in turn, has the aforementioned circumferentially distributed discharge channels 18, which are fed by the cooling oil circulating in the annular groove 27. This eliminates the need for a torsion-oriented joining of the support ring 14 to the rotor shaft 2. It is clear that instead of exactly one transverse channel 17, several transverse channels 17 can also be present in the rotor shaft 2.

[0025] List of reference numbers) Assembly ) Rotor shaft ) Slip ring unit ) Brush module ) Bottom side ) Bottom side a) Brush support plate b) Brush support plate ) Brush ) Brush 0) Current collection ring 1 ) Current collection ring 2) Shell surface 3) Outer shell 4) Support ring 5) Brush current collection ring contact 6) Feed channel 7) Cross channel 8) Discharge channel 9) Mouth 0) Inner edge 1 ) Support plate 2) Baffle surface 3) Brush support plate side 4) Brush support plate side 5) Exit area 6) Inlet area 7) Annular groove 8) Brush spring 9) Brush spring

Claims

Patent claims 1. Assembly (1) of an electric drive machine of a motor vehicle, with a rotor shaft (2), a slip ring unit (3) on the rotor shaft (2) and a brush module (4) comprising the slip ring unit (3), which has a central support plate (21), on each of whose bottom sides (5, 6) a brush support plate (7a, 7b) with at least one current-conducting brush (8, 9) is applied at least indirectly, 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 unit (3), which current collection rings (10, 11) lie on a jacket surface (12) of a support ring (14) joined to an outer jacket (13) of the rotor shaft (2) as a component of the slip ring unit (3), wherein for cooling a brush-current collection ring contact (15) is longitudinally through the rotor shaft (2) a supply channel (16) for oil runs,which in the slip ring unit (3) is intersected by at least one transverse channel (17) for the oil in the rotor shaft (2), which is connected to at least one discharge channel (18) for the oil through the support ring (14), and wherein an opening (19) of the respective discharge channel (18) is located on the outer surface (12) of the support ring (14) between the two current collection rings (10, 11).

2. Assembly according to claim 1, wherein the at least one discharge channel (18) leads radially through the support ring (14), is placed at a center between its current collection rings (10, 11) and is directed towards an inner edge (20) of the support plate (21) of the brush module (4).

3. Assembly according to claim 1 or 2, wherein an inner edge (20) of the support plate (21) of the brush module (4) in the peripheral section of the respective brush (8, 9) is present as a bevelled baffle surface (22) for redirecting the oil emerging from the discharge channel (18) in the direction of the respective brush current collection ring contact (15).

4. Assembly according to claim 1, wherein for each brush support plate side (23, 24) of the brush module (4) at least one discharge channel (18) is provided, which rather, the respective discharge channel (18) leads obliquely through the support ring (14) and is directed towards the brush current collection ring contact (15) of the respective brush support plate side (23, 24).

5. Assembly according to claim 1, wherein an exit 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).

6. 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), one transverse channel (17) is in each case aligned with a discharge channel (18).

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