DE102017108887A1 - Protective element and bearing assembly with this - Google Patents

Abstract

The present invention initially relates to a protective element (02) for protecting a mechanical bearing from damage by electrical discharge. The protective element (02) is formed as an elastic disc and consists of a composite material comprising carbon fibers (16). The protective element (02) further comprises a first contact surface (11) which is arranged axially at a first disc radius and a second contact surface (12), which is arranged axially at a second disc radius. The first contact surface (11) can be applied directly to a first bearing ring (03, 04). The second contact surface (12) can be applied directly to a second bearing ring (03, 04). The contact surfaces (11, 12) are electrically conductive and form an electrical path together with the carbon fibers (16) located in the composite material. Furthermore, the invention relates to a bearing assembly (01) comprising the protective element (02).

Description

The present invention relates to a protective member for protecting a mechanical bearing from damage by electrical discharge. The invention also relates to a bearing assembly with this protective element.

In electrical machines have the mechanical bearings, it regularly leads to sudden power transitions over the bearing parts, resulting in damage to these. There are known bearing protection rings that can be used in mechanical bearings that can derive electrical voltage / currents by means of circumferentially distributed carbon fiber brushes. A protective function against penetrating dirt or the like does not offer these bearing protection rings, which also the electrical conductivity is limited.

In the DE 10 2009 036 856 A1 an electric machine is described with a rolling bearing having a liquid in a space between the inner ring and the outer ring, which protects the rolling bearing against electrical breakdown.

The DE 10 2014 204 719 A1 describes a rolling bearing unit with protection against damage by electrical discharges, which has, in addition to an inner and an outer bearing ring, rolling elements and a protective shield. The shield is disposed between the bearing rings and has on the surface of a body part on an electrically conductive seal and a current-conducting element.

The object of the present invention, starting from the prior art, is to provide a simplified protective element which protects a mechanical bearing from electrical discharges. Furthermore, the protective element should be easy to install and protect a storage room from dirt.

According to the invention, the object is achieved by a protective element according to the appended claim 1. Furthermore, the solution is carried out by a bearing assembly according to claim 4.

The protective element according to the invention serves to protect a mechanical bearing against damage by electrical discharge, wherein the protective element can be installed in the mechanical bearing. The protective element consists of a composite material. Composites are known to consist of two or more materials. The composite material of which the protective element is made is preferably a fiber composite material. Fiber composites are known to be a combination of particles or fibers embedded in another component, the matrix. The composite of the protective element comprises carbon fibers. The protective element is formed as an elastic disc having a first and a second contact surface. The elastic disc comprises the carbon fibers and is therefore electrically conductive. The first contact surface is axially at a first disk radius and the second contact surface is arranged axially at a second disk radius. The first contact surface is axially directly on a first bearing ring can be applied, whereby a contact between the protective element and the first bearing ring is constructed. The second contact surface is axially directly on a second bearing ring can be applied, whereby a contact between the protective element and the second bearing ring is constructed. The two contact surfaces are electrically conductive. Together with the carbon fibers in the composite, the contact surfaces form an electrical path through which electrical currents can flow. Thus, the passage of current can be avoided, for example, in the bearing located rolling elements.

Preferably, the two contact surfaces are formed on the same axial side of the protective element, wherein the contact surfaces are spaced apart. The contact surfaces are formed as superficial areas.

The contact surfaces are preferably formed of carbon fibers, so that the electrical conductivity is ensured. Alternatively, preferably, the contact surfaces of a different material, which is electrically conductive. The contact surfaces are preferably formed polyamide-free.

The matrix of the composite material is preferably made of a plastic. Particularly preferably, the matrix consists of polyamide. Alternatively, preferably, the matrix consists of PET, PPA, PPS, PEEK or polyimide.

In one embodiment, the composite material consists of a plastic matrix with embedded carbon fibers and another conductive filler. The filler is preferably a metal. Alternatively, the filler is a graphite. The electrically conductive filler serves to optimize the functionality of the current dissipation. Graphite has the advantage that it has a reduced friction in the case of the sliding contact due to its layer structure. Likewise, the thermal conductivity is increased by the composite material with the further filler, so that when friction occurs, the heat can be better dissipated.

Preferably, the carbon fibers are incorporated in the matrix so that a continuous electrical path can form. Particularly preferably, the carbon fibers are continuously aligned radially in the protective element.

Preferably, the protective element has at least one third contact surface, with which the protective element can be in contact with another component. Preferably, the further component is a bearing component. The third contact surface lies axially opposite the first contact surface.

Due to the elastic structure of the protective element, due to the selected composite material, the protective element has the advantage of a resilient component that allows the automatic adjustment of the protective element in case of wear. Occurring wear is therefore automatically compensated. The amount of the axial force of the protective element is determined by the elasticity of the same, wherein the elasticity of the selected composite material is dependent.

Preferably, a metallic additional element is arranged in or on the protective element that determines the axial force of the protective element. For example, the additional element is a spring element.

An advantage of the protective element is, in addition to protection against electrical discharge, the additional protection against an ingress of medium, especially dirt. As a result, the mechanical bearing is protected against dirt when the protective element is installed. Also, the protective element can not be influenced by soiling and / or grease, so that the current dissipation is permanently ensured even in corrosive environmental conditions.

Another advantage is the ease of manufacture and assembly of the protective element in a mechanical bearing. It is also advantageous that the carbon fibers used reduce the friction in the mechanical bearing compared to other materials, such as plastic or metal.

The geometry of the protective element, such as size or diameter, can be adjusted according to the transition resistance to be set and the required friction torque.

In one embodiment, the first contact surface and the second contact surface may be formed as a common contact surface, which is continuously formed axially on the protective element.

The bearing assembly according to the invention comprises a first bearing ring and a second bearing ring, wherein both bearing rings are rotatable relative to each other about a common axis. Rolling elements are arranged between the bearing rings. Furthermore, the bearing arrangement comprises a protective element, which corresponds to the protective element described above. The protective element serves to protect the bearing rings and in particular the rolling elements from damage by electrical discharge. The first contact surface of the protective element abuts against the first bearing ring. The second contact surface of the protective element abuts against the second bearing ring.

Preferably, the first contact surface of the protective element on the first bearing ring rotatably axially fixed and the second contact surface of the protective element is located on the second bearing ring axially, so that the protective element can slide with this area on the second bearing ring along. Alternatively preferably, the second contact surface of the protective element on the second bearing ring rotatably axially fixed and the first contact surface of the protective element is located on the first bearing ring axially. Accordingly, the protective element is attached to either the first or on the second bearing ring rotatably and abuts the other bearing ring.

Preferably, the first bearing ring is an outer ring of the bearing and the second bearing ring is an inner ring of the bearing. Alternatively preferably, the first bearing ring is an inner ring and the second bearing ring is an outer ring of the bearing.

In one embodiment, the protective element between the first bearing ring and a housing component o.ä. arranged or clamped, wherein the first contact surface bears against the first bearing ring and the third contact surface on the housing component.

Preferably, the protective element is arranged with a biasing force on the bearing rings, so that there is a sustained mechanical and electrical contact.

• 1 eine Schnittansicht einer ersten Ausführungsform einer erfindungsgemäßen Lageranordnung mit Schutzelement;
• 2 eine Schnittansicht einer zweiten Ausführungsform der Lageranordnung mit Schutzelement.

Further advantages and details of the present invention will become apparent from the following description of preferred embodiments, with reference to the drawings. Show it:

• 1 a sectional view of a first embodiment of a bearing arrangement according to the invention with protective element;
• 2 a sectional view of a second embodiment of the bearing assembly with protective element.

1 shows a sectional view of a first embodiment of a bearing assembly according to the invention 01 with a protective element according to the invention 02 , The bearing arrangement 01 includes next to the protective element 02 an outer bearing ring 03 and an inner bearing ring 04 , Between bearing rings 03 . 04 are rolling elements 06 arranged on ring tracks 07 roll. The rolling element has a partially surrounding Wälzkörperkäfig 08 on. On the outer bearing ring 03 is a housing 09 arranged. Axial between the housing 09 and the outer bearing ring 03 is the disc-shaped protective element 02 clamped. The protective element 02 consists of a fiber composite material, which is composed of a polyamide matrix or plastic matrix and arranged therein carbon fibers. The plastic determines the elasticity of the protective element 02 , The protective element 02 has a plurality of contact surfaces, wherein a first contact surface 11 is formed axially on the protective element and the protective element with this contact surface 11 on the outer bearing ring 03 is applied. On the same axial side of the protective element 02 this has a second contact surface 12 on, with the protective element 02 on the inner bearing ring 04 is applied. During operation of the bearing, the second contact surface slides 12 along the inner bearing ring 04 , The first contact surface 11 lies axially opposite a third contact surface 13 , The protective element 02 lies with the third contact surface 13 on the housing 09 at. The contact surfaces 11 . 12 . 13 are electrically conductive. Together with the carbon fibers in the composite form the contact surfaces 11 . 12 . 13 an electrical path through which electrical currents can flow. The protective element 02 thus protects the bearing and in particular the rolling elements 06 before electrical discharges. Likewise, the protective element protects 02 against the ingress of contaminants into the bearing.

2 shows a sectional view of a second embodiment of the bearing assembly 01 with the protective element 02 , At first this is similar in the 2 shown protective element 02 the in 1 shown. Deviating from 1 has the in 2 shown protective element 02 a spring element 14 on, that the protective element 02 both stability and flexibility. By the spring element 14 has the protective element 02 a biasing force. The spring element 14 is disc-shaped and has a radius at a curved end, which is the tight fit of the protective element 02 on the outer bearing ring 03 serves. Furthermore, in 2 the radially oriented carbon fibers 16 as well as the plastic matrix 17 of the protective element 02 shown. Due to the radial orientation of the carbon fibers 16 in the plastic matrix 17 is an optimal electrical conductivity between the bearing rings 03 . 04 ensured. The carbon fiber 16 runs in the protective element 02 from the first contact surface 11 to the second contact surface 12 ,

LIST OF REFERENCE NUMBERS

01

bearing arrangement

02

protection element

03

Outer bearing ring

04

Inner bearing ring

05

-

06

rolling elements

07

Ringbahn

08

Rolling Element

09

casing

10

-

11

first contact surface

12

second contact surface

13

third contact surface

14

spring element

15

-

16

Carbon fiber

17

Plastic matrix

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102009036856 A1 [0003]
• DE 102014204719 A1 [0004]

Claims (4)

A protective member (02) for protecting a mechanical bearing from electric discharge damage, wherein the protective member (02) is made of a composite material comprising carbon fibers (16), and wherein the protective member (02) is formed as an elastic disc comprising a first one Contact surface (11), which is arranged axially at a first disc radius and a second contact surface (12), which is arranged axially at a second disc radius, wherein the first contact surface (11) on a first bearing ring (03, 04) is directly applied and the second contact surface (12) on a second bearing ring (03, 04) is directly applied, and wherein the contact surfaces (11, 12) are electrically conductive and together with the carbon fibers (16) in the composite form an electrical path. Protective element (02) after Claim 1 , characterized in that the contact surfaces (11, 12) only carbon fibers (16) or an electrically conductive material. Protective element (02) after Claim 1 or 2 , characterized in that the protective element (02) has at a first contact surface (11) having a third radius contact surface (13) axially opposite the first contact surface (11), wherein the third contact surface (13) on another component ( 09) can be applied. Bearing arrangement (01) with a first bearing ring (03, 04) and a second bearing ring (03, 04) which are rotatable relative to one another, wherein rolling bodies (06) are arranged between the bearing rings (03, 04), comprising a protective element (02) according to the Claims 1 to 3 which protects the bearing rings (03, 04) and the rolling elements (06) against damage by electrical discharge, wherein the first contact surface (11) of the protective element (02) bears against the first bearing ring (03, 04) and the second contact surface (12 ), wherein an electrical path is formed via the contact surfaces (11, 12) and the carbon fibers (16) contained in the composite material of the protective element (02).

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