DE102020127665B3 - Protection element and bearing arrangement with this - Google Patents

Abstract

The present invention initially relates to a protective element (02) for protecting a mechanical bearing from damage caused by electrical discharge. The protective element (02) is designed as an elastic disc and consists of a composite material that includes carbon fibers (16) and in which the carbon fibers of the composite element are designed to be exposed and aligned uniformly centrally to the center of the protective element (02). In addition, there is protection against fraying of the carbon fibers by sewing. The protective element (02) also includes a first contact area (11) which is arranged axially or radially on a first disc radius and a second contact area (12) which is arranged axially on a second disc radius. The first contact area (11) can be placed directly on a first bearing ring (03; 04). The second contact area (12) can be placed directly on a second bearing ring (03; 04). The contact areas (11, 12) are designed to be electrically conductive and, together with the carbon fibers (16) in the composite material, form an electrical path. The invention also relates to a bearing arrangement (01) which comprises the protective element (02).

Description

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

In the case of electrical machines which have mechanical bearings, there are regularly sudden current transfers via the bearing parts, which leads to damage to these. Bearing protection rings are known which can be used in mechanical bearings which can discharge electrical voltage/currents by means of carbon fiber brushes distributed around the circumference. These bearing protection rings do not offer a protective function against the ingress of dirt or the like, which also limits the electrical conductivity.

In the DE 10 2009 036 856 A1 an electrical machine with a roller bearing is described, which has a liquid in a space between the inner ring and the outer ring, which protects the roller bearing from electrical breakdowns.

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

In the DE 10 2017 108 887 A1 a protective element is presented which serves to protect a mechanical bearing from damage caused by electrical discharge. The protective element is in the form of a disc, which abuts axially on a first and a second contact surface.

Based on the prior art, the object of the present invention is to provide a protective element which protects a mechanical bearing in an improved form against damage caused by the passage of current.

According to the invention, the object is achieved by a protective element according to appended claim 1. Furthermore, the solution is achieved by a bearing arrangement according to claim 3.

The protective element according to the invention serves to protect a mechanical bearing from damage caused by electrical discharge, the protective element being able to 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 from which the protective element is made is preferably a fiber composite material. Fiber composite materials are known to be a combination of particles or fibers embedded in another component, the matrix. The composite material of the protection element has carbon fibers. The protective element is designed as an elastic disc which has a first and a second contact area. The elastic disc includes the carbon fibers and is therefore electrically conductive. The first contact area is located at a first disk radius, radially or axially, and the second contact area is located radially, axially or obliquely at a second disk radius. The first contact area can be placed axially or radially directly on a first bearing ring, as a result of which contact is established between the protective element and the first bearing ring. The second contact area can be placed directly on a second bearing ring radially, axially or obliquely, as a result of which contact is established between the protective element and the second bearing ring. The two contact areas are designed to be electrically conductive. Together with the carbon fibers in the composite material, the contact areas form an electrical path through which electrical currents can flow. As a rule, the user uses fiber composite discs, which are produced from prefabricated semi-finished products, mostly blanks, i.e. are assembled mechanically or by laser cutting and then finished. The reason for this is that large circuit boards can be manufactured easily and inexpensively. The carbon fibers, mostly in the form of fabric, are aligned either at 0°, 45° or 90°, or a combination, to the longitudinal axis of the board. In the special case presented here, aligned carbon fibers are used, which are evenly aligned in the composite element centrally to the center of the protective element. This has the advantage that there is an increase in electrical conductivity, since carbon fibers are primarily conductive in the direction of the fibers and as a result, the passage of current through, for example, rolling elements in the bearing is avoided in the application.

The contact areas of the protective element are preferably made of carbon fibers to ensure electrical conductivity. Alternatively, the contact areas are preferably made of a different material that is electrically conductive. The contact areas are preferably formed without polyamide.

The matrix of the composite material preferably consists of a plastic. The matrix particularly preferably consists of polyamide. Alternatively the matrix preferably 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 preferably the filler is a graphite. The electrically conductive filler serves to optimize the functionality of the current dissipation. Graphite offers the advantage of reduced friction in the case of sliding contact due to its layered structure. Likewise, the thermal conductivity is increased by the composite material with the additional filler, so that the heat can be better dissipated when friction occurs.

The carbon fibers (16) in the contact area (11 or 12) of the protective element that is not intended for movement are designed to be exposed. This has the advantage that particularly little friction occurs between the contact surface and the pane, since there is increased elasticity in this area due to the absence of the matrix fabric. Protection against fraying and loss of the fibers and fiber tips is provided in order to avoid fraying of the fabric or the fiber arrangement, as well as breaking of the fiber tips caused by a change in the direction of movement. This protection is realized by means of concentric sewing in the free fiber area. This stabilizes the fibers and creates a fiber composite by inserting a yarn or thread, which can be made of carbon fibers or another conductive or non-conductive material.

In a further embodiment, the protective element (02) can have a third contact area (13) on a radius having the first contact area (11), which is axially opposite the first contact area (11), the third contact area (13) being on a further component ( 09) can be applied. Furthermore, a radially outer area (14) can be present.

The associated bearing arrangement comprises a first bearing ring and a second bearing ring, both bearing rings being rotatable relative to one another about a common axis. Rolling elements are arranged between the bearing rings. Furthermore, the bearing assembly includes 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 caused by electrical discharge. The first contact area of the protective element bears against the first bearing ring. The second contact area of the protective element bears against the second 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, the first bearing ring is preferably an inner ring and the second bearing ring is an outer ring of the bearing.

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

In one embodiment, the protective element is arranged or clamped between the first bearing ring and a housing component or the like, with the first contact surface bearing on the first bearing ring and the third contact surface on the housing component.

• 1 eine Schnittansicht einer ersten Ausführungsform einer erfindungsgemäßen Lageranordnung mit Schutzelement,
• 2 eine Vorderansicht des Schutzelements,
• 3 eine Vorderansicht des Schutzelements in einer weiteren Ausführungsform.

Further advantages and details of the present invention result from the following description of preferred embodiments, with reference to the drawing. Show it:

• 1 a sectional view of a first embodiment of a bearing arrangement according to the invention with a protective element,
• 2 a front view of the protective element,
• 3 a front view of the protective element in a further embodiment.

1 shows a sectional view of a first embodiment of a bearing arrangement 01 according to the invention with a protective element 02 according to the invention. In addition to the protective element 02, the bearing arrangement 01 comprises an outer bearing ring 03 and an inner bearing ring 04. Between the bearing rings 03, 04 are arranged rolling elements 06, which roll on ring tracks 07. The rolling element has a partially surrounding rolling element cage 08 . A housing 09 is arranged on the outer bearing ring 03 . The disk-shaped protective element 02 is clamped axially between the housing 09 and the outer bearing ring 03 . The protective element 02 consists of a fiber composite material, which is composed of a polyamide matrix or plastic matrix and carbon fibers arranged therein. The plastic determines the elasticity of the protective element 02.

The protective element 02 has a plurality of contact areas, with a first contact area 11 being formed axially on the protective element and the protective element resting against the outer bearing ring 03 with this contact area 11 . On the same axial side of the protective element 02, the latter has a second contact area 12, with which the protective element 02 bears against the inner bearing ring 04. Depending on the assembly situation, the electrical contact can also or exclusively take place via a contact area 14 lying axially on the outside. During operation of the bearing, the second contact area 12 slides along the inner bearing ring 04. Dem A third contact area 13 is located axially opposite the first contact area 11. The protective element 02 rests against the housing 09 with the third contact area 13. The contact areas 11, 12, 13, 14 are designed to be electrically conductive. Together with the carbon fibers located in the composite material, the contact areas 12 and 11 and/or 13 and/or 14 form an electrical path via which electrical currents can flow. The protective element 02 thus serves to protect the bearing and in particular the rolling elements 06 from electrical discharges. The protective element 02 also protects against the ingress of contaminants into the bearing. The carbon fibers of the composite element are evenly aligned centrally to the center point of the protective element 02.

2 shows a front view of the protection element. In this case, the aligned carbon fibers of the composite element are uniformly aligned centrally to the center point M of the protective element. This has the advantage that an increase in the electrical conductivity is recorded and, as a result, the passage of current through, for example, rolling elements in the bearing is avoided in the application. The contact surfaces 11, 13, 14 are designed to be electrically conductive, as is the contact area 12, which can bear against the contact surface 18 radially, axially or obliquely.

3 shows a front view of the protective element, the open fibers being held together by sewing or embroidering 15 at the area contacting the contact surface 18 . Optionally, it is also possible in the area 11, 13, 14 to give the carbon fibers 16 a cohesion with the same or other methods.

Reference List

01

bearing arrangement

02

protective element

03

outer bearing ring

04

inner bearing ring

05

-

06

rolling elements

07

Ringbahn

08

rolling element cage

09

Housing

10

-

11

first contact area

12

second contact area

13

third contact area

14

fourth contact area

15

embroidery seam

16

Carbon fiber

17

plastic matrix

18

contact surface

Claims (3)

Protective element (02) for protecting a mechanical bearing from damage caused by electrical discharge, wherein the protective element (02) consists of a composite material that includes carbon fibers (16), and wherein the protective element (02) is designed as an elastic disk, comprising a first Contact area (11) which is arranged on a first disc radius and a second contact area (12) which is arranged on a second disc radius, the first contact area (11) being able to be placed directly on a first bearing ring (03; 04) and the second Contact area (12) can be placed directly on a second bearing ring (03; 04), and wherein the contact areas (11, 12) are designed to be electrically conductive and these, together with the carbon fibers (16) in the composite material, are uniformly centered on the center point of the protective element (02) are aligned, form an electrical path, characterized in that vorgese on the non-movement henen contact area (11 or 12), the carbon fibers (16) are designed to be exposed and the protective element (02) has protection against fraying of the carbon fibers by means of sewing. Protective element (02) according to one of the preceding claims, characterized in that the protective element (02) has a third contact area (13) on a radius having the first contact area (11), which is axially opposite the first contact area (11), the third Contact area (13) can be applied to a further component (09). Bearing arrangement (01) with a first bearing ring (03; 04) and a second bearing ring (03; 04), which can be rotated in relation to one another, with rolling elements (06) being arranged between the bearing rings (03, 04), comprising a protective element (02) according to the claims 1 or 2 , which protects the bearing rings (03, 04) and the rolling elements (06) from damage caused by electrical discharge, the first contact area (11) of the protective element (02) lying against the first bearing ring (03; 04) and the second contact area (12 ) of the protective element (02) rests against the second bearing ring (03; 04), and via the contact areas (11, 12) and contained in the composite material of the protective element (02). Tenen carbon fibers (16) an electrical path is formed.

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