DE102019212499A1 - Device for an electrically conductive connection between a shaft and a housing - Google Patents

Abstract

A device is proposed for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1), comprising an electrically conductive holding element (3) connected to the housing (1) and a electrically conductive contact element (3) attached to it and electrically conductively connected to the shaft (2) via a sliding contact, the holding element (3) being attached to the housing (1) by means of two or more screw connections (5) for axial positioning, wherein the radial centering of the holding element (3) takes place through a corresponding receptacle in the housing (1) and wherein the holding element (3) has cranked lugs (6) for connection to the screw connection points (5).

Description

The present invention relates to a device for the electrically conductive connection between a shaft and a housing according to the preamble of claim 1. Furthermore, the invention relates to a drive train unit for a motor vehicle with a device according to the invention.

In the case of shafts rotatably mounted in housings, it is often necessary to establish an electrically conductive connection between the shaft and the housing via a separate device for earthing purposes, since the lubricants used in the shaft bearings do not guarantee a reliable electrically conductive connection between the shaft and the housing can.

From the DE 10 2015 110 428 A1 a sliding contact element for producing an electrical contact between a first sliding partner of the sliding contact element and a second sliding partner of the sliding contact element is known, wherein the first sliding partner has an electrical conductor and an electrical contact surface and the second sliding partner comprises an electrical counter-contact surface which during the movement of the second sliding partner can be placed relative to the first sliding partner on the contact surface of the first sliding partner for making the electrical contact.

Here it is provided that the sliding contact element comprises a contact element made of a first material of a sliding bearing material as an essential component, that the contact surface is formed on the contact element, which is formed in sections from an electrically conductive second material, which is arranged flush with the surrounding first material and with the electrical conductor is electrically connected and that the electrical conductivity of the second material is higher than that of the first material. The contact element is pressed against the mating contact surface with a defined force by means of flexible clamping means.

From the DE 10 2012 213 920 A1 shows a gear unit with a gear housing, an input shaft mounted in the gear housing via at least one bearing arrangement and connectable to an electric drive machine and with a grounding device associated with the input shaft and at least indirectly connected to the gear housing. In the known gear unit it is provided that the grounding device is arranged on the input side of the input shaft in the gear housing in the direction of force flow in front of the first bearing arrangement, wherein the grounding device can be positively connected to the gear housing by means of a screw connection.

Furthermore, from the DE 10 2016 010 926 A1 a shaft grounding ring known, for diverting induced voltages or electrical charges from a first machine element, preferably a shaft, into a second machine element, with an annular housing made of electrically conductive material, which is conductively connected to one machine element and with at least one discharge element is in electrically conductive connection, which also consists of an electrically conductive material and is in electrically conductive connection with the other machine element, the discharge element being a disk-shaped discharge body extending at least over part of the circumference.

The present invention is based on the object of specifying a device for the electrically conductive connection between a shaft and a housing. Furthermore, a drive train unit for a motor vehicle with a device according to the invention is to be specified.

This object is achieved for a device by the features of claim 1. A drive train unit for a motor vehicle is the subject matter of patent claim 8. Further embodiments and advantages according to the invention emerge from the corresponding subclaims.

Accordingly, a device for the electrically conductive connection between a shaft rotatably mounted in a housing and the housing is proposed, which has an electrically conductive holding element connected to the housing in an electrically conductive manner and an electrically conductive holding element attached to it in an electrically conductive manner and electrically conductive with the shaft via a sliding contact having connected contact element, wherein the holding element for axial positioning is fastened to the housing by means of two or more, preferably three screwing points, the radial centering of the holding element takes place through a corresponding receptacle in the housing and wherein the holding element has cranked flags for connection to the screwing points. By being fastened to the housing, the holding element is pressed against a corresponding contact surface of the housing, whereby an electrically conductive connection is realized between the housing and the holding element.

According to one embodiment of the invention, an electrically conductive slip ring can be applied to the shaft, over the circumference of which there is a sliding contact with the contact element of the device, the surface of the shaft alternatively has electrically conductive layer applied by means of cold gas spraying, over the circumference of which there is a sliding contact with the contact element of the device.

According to the invention, the contact element can be designed as a resilient PTFE element having a grinding surface or as a carbon brush.

The concept according to the invention realizes a grounding function with little constructional outlay, with simple assembly and non-destructive disassembly being made possible in an advantageous manner. Furthermore, the device according to the invention requires little axial and radial installation space, with the provision of the cranked lugs for connecting the holding element to the screw connection points ensuring elasticity to compensate for tolerances. In addition, an anti-twist device is implemented through axial positioning and pre-tensioning via the screw connection points.

The device according to the invention can be integrated into a drive train unit for a motor vehicle, wherein the drive train unit can have an electric axle drive, an automated transmission or an automatic transmission.

Here, the shaft, which is electrically conductively connected to a housing by means of the device according to the invention, can be an input shaft or an output shaft of the drive train unit, wherein the drive train unit can have an electric machine to drive the shaft.

• 1: Eine schematische Schnittansicht einer ersten Ausgestaltung der Erfindung;
• 2: Eine schematische Schnittansicht einer zweiten Ausgestaltung der Erfindung; und
• 3: Eine perspektivische Ansicht der Ausgestaltung gemäß 1 zur Veranschaulichung der axialen Positionierung des Halteelementes mittels Verschraubungen.

The invention is explained in more detail below with reference to the accompanying figures. Show it:

• 1 : A schematic sectional view of a first embodiment of the invention;
• 2 : A schematic sectional view of a second embodiment of the invention; and
• 3 : A perspective view of the embodiment according to FIG 1 to illustrate the axial positioning of the holding element by means of screw connections.

In 1 is one in one case 1 bearing shaft 2 shown. According to the invention, a device for the electrically conductive connection between the in the housing 1 rotatable shaft 2 and the case 1 one with the case 1 electrically conductive connected electrically conductive holding element 3 and an electrically conductive attached thereto, electrically conductive and connected to the shaft 2 Contact element connected in an electrically conductive manner via a sliding contact 4th on. The contact element 4th viewed radially between the shaft 2 and one parallel to the shaft 2 extending part of the holding element 3 arranged.

According to the invention and referring to 3 is the holding element 3 for axial positioning using three screw connection points 5 on the housing 1 attached, the radial centering of the holding element 3 through a corresponding receptacle in the housing 1 he follows. It is provided here that the holding element 3 for connection to the screw connection points 5 cranked flags 6th having. The contact area between the holding element 3 and the case 1 is formed by an annular surface that is coaxial with the axis of rotation of the shaft 2 is arranged.

In the example shown, the contact element is 4th designed as a resilient PTFE (polytetrafluoroethylene) element having a grinding surface. Through the sliding contact between the shaft 2 and the contact element 4th by the electrically conductive fastening of the contact element 4th on the holding element 3 and through the electrically conductive connection of the holding element 3 with the case 1 becomes an electrically conductive connection in the housing 1 rotatably mounted shaft and the housing 1 created. The small radial installation space required advantageously creates an axial force-absorbing surface 9 reserved for the assembly or pressing-in of components.

The in 1 The embodiment shown is a dust cover 7th provided which is the sliding contact point between the shaft 2 and the contact element 4th protects against environmental influences such as salt, dust, etc., viewed axially on the housing 1 remote side of the holding element 3 is arranged and on the holding element 3 is applied. The dust cover 7th can for example be formed from a preferably impregnated fleece, from PTFE or from an elastomer. Furthermore, in the example shown, the device according to the invention is in a drive train unit, viewed axially, adjacent to a radial shaft sealing ring 8th arranged, which between the housing 1 and the wave 2 works.

The embodiment according to 2 differs from the embodiment according to 1 in that there is no dust cover to protect the sliding contact point between the shaft 2 and the contact element 4th is provided against environmental influences, whereby the device according to the invention can be made particularly compact viewed axially. The sliding contact point is protected from environmental influences in the exemplary embodiment according to FIG 2 through an additional housing, which is attached to the housing 1 is attached. The additional housing is in 2 not shown. Also in the example after 3 is the contact element 4th viewed radially between the shaft 2 and one parallel to the shaft 1 extending part of the holding element 3 arranged.

Advantageously, in the configurations according to 1 and 2 for screwing the retaining element 3 the same pitch circle diameter can be kept for the position of the screw connection so that the same partially automated screwing tool can be used. Furthermore, the radial shaft seal 8th , even if the device according to the invention is not required, can be installed in both variants with the same driving tool.

List of reference symbols

1

casing

2

in the housing 1 rotatably mounted shaft

3

Retaining element

4th

Contact element

5

Screwing point

6th

banner

7th

Dust protection

8th

Radial shaft seal

9

Force absorption area

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015110428 A1 [0003]
• DE 102012213920 A1 [0005]
• DE 102016010926 A1 [0006]

Claims (11)

Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1), comprising an electrically conductive holding element (3) connected to the housing (1) and an electrically conductive holding element (3) attached thereto , electrically conductive contact element (3) electrically connected to the shaft (2) via a sliding contact, characterized in that the holding element (3) is fastened to the housing (1) for axial positioning by means of two or more screw connections (5), wherein the radial centering of the holding element (3) takes place through a corresponding receptacle in the housing (1) and the holding element (3) has cranked lugs (6) for connection to the screw connection points (5). Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) Claim 1 , characterized in that the contact element (4), viewed radially, is arranged between the shaft (2) and a part of the holding element (3) running parallel to the shaft (2). Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) Claim 1 or 2 , characterized in that the contact element (4) is designed as a resilient PTFE element having a grinding surface or as a carbon brush. Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) Claim 1 , 2 or 3 , characterized in that a dust protection (7) is provided which protects the sliding contact point between the shaft (2) and the contact element (4) from environmental influences and is arranged on the side of the holding element (3) facing away from the housing (1) when viewed axially and rests against the holding element (3). Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) Claim 4 , characterized in that the dust protection (7) is formed from a fleece, from PTFE or from an elastomer. Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) according to one of the preceding claims, characterized in that, viewed axially, it is arranged adjacent to a radial shaft sealing ring (8) which between the housing (1) and the shaft (2) acts. Device for the electrically conductive connection between a shaft (2) rotatably mounted in a housing (1) and the housing (1) according to one of the preceding claims, characterized in that two, three or more screw connection points (5) are provided. Drive train unit for a motor vehicle, comprising a housing (1) and a shaft (2) rotatably mounted in the housing (1), characterized in that it has a device for the electrically conductive connection between the shaft (2) and the housing (1) according to a of the Claims 1 to 7th having. Drive train unit after Claim 8 , characterized in that the device for the electrically conductive connection between the shaft (2) and the housing (1) is arranged adjacent to a radial shaft sealing ring (8) which acts between the housing (1) and the shaft (2). Drive train unit after Claim 8 or 9 , characterized in that the shaft (2) is an input shaft or an output shaft of the drive train unit, wherein the drive train unit can have an electrical machine to drive the shaft. Drive train unit after Claim 8 , 9 or 10 , characterized in that it has an electric axle drive, an automated transmission or an automatic transmission.

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