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) and a collecting device (5) for the contactless removal of leakage, that penetrates through the shaft seal (4), from the shaft (1). Further, an electric machine has a rotor shaft (1) that can be driven in rotation and a seal device (3) of the type for sealing the rotor shaft (1) and, therefore, also an inside space of the electric machine. Additionally, a drive device for the electrical driving of a motor vehicle that has an electric machine of the type for the provision of a drive power of the drive device.

Claims

1-12. (canceled)

13. A seal device (3) for a rotatable shaft (1) comprising: a shaft seal (4), a collecting device (5) for the contactless removal of leakage, that penetrates through the shaft seal (4), from the shaft (1).

14. The seal device (3) according to claim 13, wherein the collecting device (5) is formed by a shoulder (5A) arranged on the shaft (1) and a collecting structure (5B) that surrounds the shoulder (5A) radially.

15. The seal device (3) according to claim 14, wherein the shoulder (5A) is formed by a shoulder (5A) of the shaft itself, or by a component attached onto the shaft (1) that radially surrounds the shaft (1).

16. The seal device (3) according to claim 14, wherein the collecting structure (5B) is formed by a housing (2) in which the shaft (1) is rotatably mounted, or is designed to be fitted on such a housing (2).

17. The seal device (3) according to claim 14, wherein the collecting structure (5B) is made from one of sheet metal or plastic.

18. The seal device (3) according to claim 13, wherein the seal device (3) comprises a shaft grounding connection (6).

19. The seal device (3) according to claim 18, wherein the shaft seal (4), the shaft grounding connection (6) and the collecting device (5) are axially arranged one behind another.

20. The seal device (3) according to claim 19, wherein the shaft grounding connection (6) is arranged axially between the shaft seal (4) and the collecting device (5).

21. The seal device (3) according to claim 19, wherein the collecting device (5) is arranged axially between the shaft seal (4) and the shaft grounding connection (6).

22. The seal device (3) according to claim 18, wherein the shaft grounding connection (6) is arranged on a collecting structure (5B).

23. 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 formed according to claim 13.

24. A drive device for electrically driving a motor vehicle, comprising an electric machine for provision of a drive power of the drive device, wherein the electric machine is formed according to claim 23.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Below, the invention is explained in greater detail with reference to figures from which further preferred embodiments and features of the invention emerge. In each case schematically, the figures show:

[0025] FIG. 1: A partial view of a longitudinal section through an electric machine in the area of a seal device,

[0026] FIG. 2: A partial view of a longitudinal section through an electric machine in the area of a seal device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In the figures, the same or at least functionally equivalent components or elements are denoted by the same indexes.

[0028] 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 the 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, here for example a radial shaft seal, and a collecting device 5 axially a distance away from it, and a shaft grounding connection 6, here 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.

[0029] The shaft seal 4 is intended to prevent the ingress of a fluid, in particular a lubricant, into the inside space of the electric machine. In practice this does not occur under all operating conditions of the electric machine. However, it can happen that a leak penetrates the shaft seal 4 and flows along the shaft 1 into the inside space of the electric machine. This is prevented by the collecting device 5, which 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 to the housing 2. The collecting structure 5B surrounds the shoulder 5A but is not in contact with it. Thus, the collecting structure 5B works in a contactless manner. The collecting structure 5B shown is made, for example, of sheet metal or plastic. The shoulder 5A forms a breakaway edge for the leakage that passes through the shaft seal 4.

[0030] When the shaft 1 rotates about the rotational axis L and during this a leak occurs through the shaft seal 4, this reaches the shoulder 5A. There, it is guided along the shoulder 5A radially outward to the breakaway edge of the shoulder 5A. The breakaway edge in combination with the centrifugal force acting of the leakage at that point causes the leakage to be withdrawn and flung outward from the shoulder 5A. The outward-flung leakage is captured by the structure 5B and passed into a reservoir 7 located under the shaft seal 4. In the example embodiment shown the reservoir 7 is formed by the housing 2. Alternatively, the reservoir 7 can be formed by the collecting structure 5B itself.

[0031] In the radially inner area (i.e. in the area close to the shaft 1), the collecting structure 5B has a bent portion 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 flung upward and is caught there by collecting structure 5B and then flows along the collecting structure 5B and the pot shape into the reservoir 7, without dripping back onto the shaft 1. As can be seen in FIG. 1, the collecting structure 5B can otherwise be saucer-shaped.

[0032] The shaft grounding connection 6 serves for the permanent electrical connection of the shaft 1 to the housing 2 as the electrical reference potential. In that way, bearings 8 for mounting the shaft 1 in the housing 2 are protected against damage that can occur at the bearings 8 by virtue of electrical potential differences.

[0033] The shaft grounding connection 6 is arranged axially, relative to a rotational axis L, between the collecting device 5 and the shaft seal 4. These elements 4, 5 and 6 are directly adjacent to one another. However, otherwise than this the collecting device 5 can also be arranged axially between the shaft grounding connection 6 and the shaft seal 4.

[0034] Axially adjacent to the shaft seal 4 and outside the inside space of the electric machine is located 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 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.

[0035] FIG. 2 shows an embodiment of a seal device 3 which is slightly different compared with that of FIG. 1. The essential difference is that in the embodiment according to FIG. 2 no grounding connection 6 is provided. In other respects the explanations concerning the embodiment according to FIG. 1 also apply to the embodiment according to FIG. 2. In this case the inside space of the electric machine is to the right side of the shaft seal 4.

[0036] It can be provided that the seal device 3 according to FIG. 1 is arranged so as to seal the shaft 1 on a first side of an electric machine and the seal device 3 according to FIG. 2 is arranged on a second side of the electric machine opposite the first side in order to seal the shaft 1 there. A rotor of the electric machine connected to the shaft 1 is then arranged in particular axially adjacent to and between the two collecting structures 5B in FIGS. 1 and 2.

INDEXES

[0037] 1 Rotor shaft, shaft [0038] 2 Housing [0039] 3 Seal device [0040] 4 Shaft seal [0041] 5 Collecting device [0042] 5A Shaft shoulder [0043] 5B Collecting structure [0044] 6 Shaft grounding connection [0045] 7 Reservoir [0046] 8 Bearing [0047] d1 Shaft diameter [0048] d2 Shaft diameter [0049] d3 Shaft diameter [0050] L Rotation axis