BRUSH DEVICE FOR ELECTRICALLY CONNECTING A FIRST ELEMENT TO A SECOND ELEMENT, E-MACHINE AND DRIVE DEVICE

Abstract

A brush device (1) for electrically connecting a first element (2A) to a second element (2B) that can rotate relative to the first element (2A) about a rotational axis (L). In order to make electrical contact with the second element (2B), in a contact area (1A), the brush device (1) has a structure (1 B, 11B′, 1B″) that extends helically relative to the rotational axis (L). An E-machine (2) has a brush device (1) of this type, and a drive device has such an E-machine (2) for electrically driving a motor vehicle.

Claims

1-8. (canceled)

9. A brush device (1) for electrically connecting a first element (2A) to a second element (2B) that is rotatable relative to the first element (2A) about a rotational axis (L), in a contact area (1A) for forming an electrical contact with the second element (2B), the brush device (1) having a structure (1B, 1B′, 1B″) that extends helically relative to the rotational axis (L).

10. The brush device (1) according to claim 9, wherein the structure (1B, 1B′, 1B″) is formed by a plurality of electrically conductive filaments projecting to the contact area (1A), and the filaments are arranged helically relative to the rotational axis (L).

11. The brush device (1) according to claim 9, wherein the structure (1B, 1B′, 1B″) is formed by at least one solid electrical conductor that projects to the contact area (1A) such that, in the contact area, the conductor has a surface structure that extends helically relative to the rotational axis (L).

12. The brush device (1) according to claim 9, wherein the structure (1B, 1B′, 1B″) is formed by at least one lip-shaped electrical conductor that projects to the contact area (1A), and the conductor is arranged helically relative to the rotational axis (L).

13. The brush device (1) according to claim 9, wherein the helically extending structure (1B, 1B′, 1B″) is of a single-pitch or a multiple-pitch design.

14. An E-machine (2) with a rotor shaft (2B) that can rotate about a rotational axis (L) and with a brush device (1) for electrically connecting the rotor shaft (2B) to an electric reference potential (2A), wherein the brush device (1) is designed according to claim 9.

15. The E-machine (2) according to claim 14, wherein the E-machine (2) has an inside space in which a rotor, connected to the rotor shaft (2B), is rotatably arranged, the rotor shaft (2B), via a shaft seal (2C), projects out of the inside space, the brush device (1) is arranged outside the inside space and adjacent to the shaft seal (2C).

16. A drive device for electrically driving a motor vehicle, the drive device comprising an E-machine (2) for provision of a drive power of the drive device, wherein the E-machine (2) is designed according to claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Below, the invention is explained in greater detail with reference to figures from which further preferred embodiments and features of the invention can be seen. The figures show, in schematic form:

[0023] FIG. 1: A three-dimensional view of a proposed brush device,

[0024] FIG. 2: A longitudinal section through a proposed e-machine with a brush device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In the figures, the same or at least functionally identical components or elements are given the same indexes.

[0026] The brush device 1 according to FIG. 1 serves for the electrical connection of a first element, such as a housing (not shown), to a second element such as a rotatable shaft that can rotate relative to the first element. A rotational axis L of the second element extends through the center of the brush device 1. The brush device is designed, for example, to be fitted in or on an e-machine in order to connect a rotor shaft of the e-machine electrically to a housing of the e-machine and thereby to form a ground or grounding connection for the rotor shaft. An example of this is shown in FIG. 2.

[0027] According to FIG. 1, in a radially inner area 1A the brush device 1 has a structure that extends helically relative to the rotational axis. This structure is indicated by the helical lines 1B, 1B′ and 1B″. As shown, the structure can comprise several pitches (lines 1B, 1B′ and 1B″). However, the structure can also be of single-pitch design (only one of the lines 1B, 1B′ or 1B″). The structure can extend completely around the rotational axis L once or several times. However, the structure can also be formed of only one helical section.

[0028] The structure 1B, 1B′, 1B″ serves to form a sliding contact with the second element. If the brush device 1 is mounted on the second element and the first element is brought into electrical contact with the structure 11B, 11B′, 11B″ in the contact area, the electrical connection between the first and second elements is established.

[0029] The structure can be formed in that at least in a section along the line 1B, 1B′ or 1B″ shown in FIG. 1, a row of electrically conductive filaments that project as far as the contact area 1A are provided as the brush. Alternatively, the structure can be formed in that one or more solid electrical conductors projecting as far as the contact area 1A is/are provided as brushes, which at least in a section have a surface structure, in particular such as one or more grooves, that extends along the line 1B, 1B′ or 1B″ shown in FIG. 1. Alternatively, the structure can be formed in that at least in a section along the line 1B, 1B′ or 1B″ shown in FIG. 1, a lip-shaped electrical conductor projecting as far as the contact area 1A is provided.

[0030] The second element is then positioned with a surface in contact with the structure. That surface can be smooth. During rotation, the helical shape of the structure gives rise to a conveying action which sweeps particles in the contact area 1A away from the brush device (see the shape of the lines 1B, 11B′, 1B″). Depending on the rotational direction of the second element and the twist direction of the structure, in FIG. 1 the particles are swept away from the brush device 1 either forward or rearward.

[0031] FIG. 2 shows part of a longitudinal section through an e-machine 2. The figure shows part of a housing 2A of the e-machine 2 and part of a rotor shaft 2B of the e-machine 2 which is mounted to rotate in the housing. Also to be seen is a shaft seal 2C which, in the area of the rotor shaft 2B, seals an inside of the e-machine 2 relative to the outside. The shaft seal 2C is fixed in the housing 2A. The rotor shaft 2B is connected to a rotor of the e-machine 2 and can therefore be driven in rotation.

[0032] Close to the shaft seal 2C, on the outside of the e-machine 2 there is a brush device 1. This comprises the structure that extends helically relative to the rotational axis L of the rotor shaft as shown in FIG. 1 (indexed 1B, 1B′) as the actual brush. In FIG. 2 this structure is formed, for example, by two electrically conductive lips or two rows of electrically conductive filaments. As can be seen in FIG. 2, in a radially outer area these are held in a holder 1C of the brush device 1 in which they are fixed. Starting from there they project radially inward as far as the contact area 1A of the brush device 1, where they make contact with the rotor shaft 2B. The holder 1C of the brush device 1 is also electrically conductive. For example, it is made of sheet iron. Thus, there is an electrical connection between the rotor shaft 2B and the housing 2A which results in an electric potential equalization between them. Correspondingly, a connection of the rotor shaft 2B to an electric ground or an electric grounding can be formed.

[0033] By virtue of the helical structure of the brush device 1 relative to the rotational axis L of the rotor shaft, when the rotor shaft 2B rotates particles are swept out of the contact area 1A. Such particles can be produced by wear of the contact area 1A itself, or they can be in the form of lubricant particles from a leak in the nearby shaft seal 2C.

[0034] In the area axially in front of and/or behind the brush device 1, a scraper edge can be provided on the rotor shaft 2B. This facilitates the clearing away of particles from the rotor shaft 2B after they have been swept out of the contact area 1A. Likewise, in the area axially in front of and/or behind the brush device 1 a discharge opening can be provided in the housing 2A. This facilitates the complete clearing away of such particles.

INDEXES

[0035] 1 Brush device [0036] 1A Contact area [0037] 1B Line; structure [0038] 1B′ Line; structure [0039] 1B″ Line; structure [0040] 1C Holder [0041] 2 E-machine [0042] 2A Housing [0043] 2B Rotor shaft [0044] 2C Shaft seal