SEAL DEVICE, ELECTRIC MACHINE, AND DRIVE DEVICE

Abstract

A seal device (3) for a rotating shaft (1). The seal device has a shaft seal (4), a shaft grounding connection (6) and a holding feature (9) for holding the shaft seal (4) and the shaft grounding connection (6). The holding feature (9) has at least one opening (10), between the shaft seal (4) and the shaft grounding connection (6), for clearing particles away from the shaft seal (4) and the shaft grounding connection (6). An electric machine with a rotor shaft (1) that can be driven in rotation and with a seal device (3) of the above type for sealing the rotor shaft (1) and, therefore, also sealing an inside space of the electric machine. Furthermore, a drive unit for electrically driving a motor vehicle, including an electric machine of the above type for providing drive power of the drive unit.

Claims

1-16. (canceled)

17. A seal device (3) for a rotating shaft (1), the seal device comprising: a shaft seal (4), a shaft grounding connection (6), a holding feature (9) for holding the shaft seal (4) and the shaft grounding connection (6), and the holding feature (9) having at least one opening (10), between the shaft seal (4) and the shaft grounding connection (6), for clearing particles away from the shaft seal (4) and the shaft grounding connection (6).

18. The seal device (3) according to claim 17, wherein the opening (10) is arranged such that the opening, in a correctly assembled position of the seal device (3), is at least one of under the shaft seal (4) and under a brush of the shaft grounding connection (6).

19. The seal device (3) according to claim 17, wherein the holding feature (9) is formed by a housing section of a housing (2).

20. The seal device (3) according to claim 19, wherein a bearing (8) is provided on the housing section (2), and the bearing rotatably supports the shaft (1) in the housing (2).

21. The seal device (3) according to claim 19, wherein the housing section (9) is formed by a locally thickened portion of the housing (2) that surrounds the shaft in a ring shape, with a plurality of openings (10) distributed around a circumference of the locally thickened portion.

22. The seal device (3) according to claim 17, wherein the at least one opening (10) leads to a reservoir (7) for the particles.

23. The seal device (3) according to claim 17, wherein the seal device (3) comprises a collecting device (5) for contactless removal of any leakage from the shaft (1) that passes through the shaft seal (4).

24. The seal device (3) according to claim 23, wherein the collecting device (5) is in a form of a shoulder (5A) arranged on the shaft (1) and a collecting structure (5B) that surrounds the shoulder (5A) radially.

25. The seal device (3) according to claim 24, wherein the shoulder (5A) is formed either by a shoulder (5A) of the shaft itself, or by a component which is fixed onto the shaft (1) and radially surrounds the shaft (1).

26. The seal device (3) according to claim 24, wherein the collecting structure (5B) is made of either sheet metal or plastic.

27. The seal device (3) according to claim 23, wherein the shaft seal (4), the shaft grounding connection (6) and the collecting device (5) are arranged one behind another.

28. The seal device (3) according to claim 27, wherein the shaft grounding connection (6) is arranged axially between the shaft seal (4) and the collecting device (5).

29. The seal device (3) according to claim 27, wherein the collecting device (5) is arranged axially between the shaft seal (4) and the shaft grounding connection (6).

30. The seal device (3) according to claim 24, wherein the shaft grounding device (6) is arranged on the collecting structure (5B) of the collecting device (5).

31. An electric machine with a rotor shaft (1) that can be driven in rotation and with a seal device (3) for sealing the rotor shaft (1), wherein the seal device (3) is configured according to claim 17.

32. A drive unit for electrically driving a motor vehicle, comprising an electric machine for provision of drive power from the drive unit, wherein the electric machine is designed in accordance with claim 31.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Below, the invention is explained in greater detail with reference to figures from which further preferred embodiments and features of the invention emerge. In schematic form, the figures show:

[0033] FIG. 1: A partial view of a longitudinal section through an electric machine in the area of a seal device,

[0034] FIG. 2: A partial three-dimensional view from above, of a holding feature of a seal device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] In the figures the same or at least functionally equivalent components or elements are denoted by the same indexes.

[0036] FIG. 1 shows part of a longitudinal section through an electric machine in the area of an axial end of the electric machine. In this area a rotor shaft 1 of the electric machine that can rotate about a rotational axis L passes through a housing 2 of the electric machine. To seal an inside space of the electric machine in the area of the shaft 1, a seal device 3 is provided. The seal device 3 comprises a shaft seal 4, in this case for example a radial shaft seal, and axially a distance away from it a shaft grounding connection 6, in this case for example a shaft grounding ring. In FIG. 1 the inside space of the electric machine is to the left of the shaft seal 4.

[0037] The shaft seal 4 and the shaft grounding connection 6 are held in position by a holding feature 9 of the seal device 3. In the present case the holding feature 9 is in the form of a housing section of the housing 2. This holding feature has at least one opening 10, which is arranged axially relative to the rotational axis L between the shaft seal 4 and the shaft grounding connection 6. The opening 10 leads radially away from the shaft seal 4 and the shaft grounding connection 6 and serves on the one hand to clear away particles from the grounding connection 6 and on the other hand to clear away particles from the shaft seal 4. In FIG. 1 this is indicated by a downward arrow by the opening 10.

[0038] The shaft seal 4 is intended to prevent the ingress of any fluid, in particular a lubricant, into the inside space of the electric machine. It can happen that some leakage passes through the shaft seal 4 and flows along the holding feature 9 axially in the direction of the shaft grounding connection 6 within the inside space. This leakage reaches the opening 10, which diverts it downward directly into a reservoir 7. Thus, the opening 10 is arranged so that when the seal device 3 is fitted correctly, the opening is positioned under the shaft seal 4. The opening 10 is also under a brush of the shaft grounding connection 6, so that particles worn off the latter also fall down through the opening 10 directly into the reservoir 7.

[0039] As shown in FIG. 1 the seal device 3 also comprises an optional collecting device 5. Namely, it can also happen that some leakage passes through the shaft seal 4 and flows along the shaft 1 into the inside space of the electric machine. In that case the leakage does not normally reach the opening 10, but is prevented from spreading further in the inside space by the collecting device 5. This can therefore also be called a leakage collecting device. In the example embodiment shown, the collecting device 5 consists of a shaft shoulder 5A on the shaft 1 and a collecting structure 5B fixed onto the housing 2. The collecting structure 5B surrounds the shoulder 5A radially but is not in contact with it. Thus, the collecting structure 5B works in a contactless manner. The collecting structure 5B illustrated consists, for example, of sheet metal or plastic. The shoulder 5A forms a breakaway edge for any leakage that has passed through the shaft seal 4 into the inside space of the electric machine.

[0040] When the shaft 1 rotates about the rotational axis L and during this a leak occurs at the shaft seal 4, the leakage gets to the shoulder 5A. There, it is diverted along the shoulder 5A radially outward to the breakaway edge of the shoulder 5A. The breakaway edge, in combination with the centrifugal force acting upon the leakage at that point, causes the leakage to become detached from and flung off the shoulder 5A. The flung-off leakage is captured by the collecting structure 5B and passed into the reservoir 7. In the example embodiment shown, the reservoir 7 is formed by the housing section which also forms the holding feature 9. Alternatively, the reservoir 7 can be formed by the collecting structure 5B itself.

[0041] In the radially inner area (i.e. in the area close to the shaft 1), the collecting structure 5B is bent over so that the radially inner end of the collecting structure 5B is pot-shaped and extends parallel to the shaft 1 toward the shoulder 5A. Leakage which is flung upward and there captured by the collecting structure 5B thus flows along the collecting structure 5B and the pot shape into the reservoir 7, without dripping back down onto the shaft 1. As can be seen in FIG. 1, the collecting structure can otherwise be saucer-shaped.

[0042] The shaft grounding connection 6 serves to form a permanent electrical connection between the shaft 1 and the housing 2 as the electrical reference potential. In that way the bearings 8 for mounting the shaft 1 in the housing 2 are protected against damage that can occur due to electrical potential differences at the bearings 8.

[0043] Relative to a rotational axis L of the shaft 1, the shaft grounding connection 6 is arranged between the collecting device 5 and the shaft seal 4. These elements 4, 5 and 6 are directly adjacent to one another. However, in a different configuration the collecting device 5 could be arranged axially between the shaft grounding connection 6 and the shaft seal 4. In this, the opening 10 is always at a suitable point between the shaft seal 4 and the shaft grounding connection 6.

[0044] Axially close to the shaft seal 4 and outside the inside space of the electric machine is the bearing 8 for the rotatable mounting of the shaft 1 in the housing 2, in this case for example in the form of a deep-groove ball bearing. The bearing 8 is also arranged on the holding feature 9 that forms part of the housing.

[0045] The bearing 8 is arranged on a first diameter d1 of the shaft 1. The shaft seal 4 and the shaft grounding connection 6 are arranged on another, second diameter d2 of the shaft 1. The shoulder 5A forms another, third diameter d3 of the shaft 1. In this case d1<d2<d3.

[0046] FIG. 2 shows as an example, a three-dimensional view of the holding feature 9 that forms part of the housing for holding the shaft seal 4 and the shaft grounding connection 6. The holding feature 9 is in the form of a local, annular thickened portion of the housing 2, which directly supports the shaft seal 4 and the shaft grounding connection 6. This thickened portion surrounds the shaft 1 indicated by the rotational axis L, which passes through the circular opening that can be seen in FIG. 2 on the inside of the holding feature 9. Around the circumference of the thickened portion are distributed a plurality of radial openings 10. These serve in each case to clear away particles from the shaft seal 4 (here, particularly in the form of leakage) and to clear away particles from the shaft grounding connect ion 6 (here, particularly in the form of wear particles).

[0047] The holding feature 9 also comprises a rib 11 (see also FIG. 1) which is arranged continuously around the rotational axis L. In this, accordingly, no radial opening is provided. The rib 11 prevents any further radial spreading of the particles discharged through the openings 10. These collect in the lower area of the rib 11. Thus, the rib 11 forms the lower edge of the reservoir 7.

[0048] The rib 7 has attachment points for fixing the collecting structure 5B. In FIG. 2 the attachment points are, as an example, in the form of threaded bores. To these can be screwed the saucer-shaped collecting structure 5B, which is made from sheet metal or plastic. However, there are other possible ways to attach the collecting structure 5B, for example by welding, riveting or clipping it firmly in place.

[0049] In an alternative embodiment it can be provided that the shaft grounding connection 6 is arranged on the collecting structure 5B and there connects the shaft 1 electrically to the housing 2. In that case therefore, the electrical connection takes place by way of the shaft grounding connection 6 and the collecting structure 5B.

INDEXES

[0050] 1 Rotor shaft, shaft [0051] 2 Housing [0052] 3 Seal device [0053] 4 Shaft seal [0054] 5 Collecting device [0055] 5A Shaft shoulder [0056] 5B Collecting structure [0057] 6 Shaft grounding connection [0058] 7 Reservoir [0059] 8 Bearing [0060] 9 Holding feature [0061] 10 Opening [0062] 11 Rib [0063] d1 Shaft diameter [0064] d2 Shaft diameter [0065] d3 Shaft diameter [0066] L Rotational axis