DE102017115353A1 - Rolling bearing assembly with a potential equalization element - Google Patents

Abstract

The invention relates to a rolling bearing arrangement (30) with a roller bearing (32) and an equipotential bonding element (10), wherein the rolling bearing (32) for supporting a shaft (50) has at least one bearing outer ring (38) and rolling elements (40) rolling thereon. According to the invention it is provided that on the bearing outer ring (38) a circular arc, radially outwardly open receiving groove (52) is formed, that the equipotential bonding element (10) is elastic and loop-like that the equipotential bonding element (10) has an elastomeric portion (12). and an electrically conductive yarn portion (14) such that the elastomer portion (12) and a first portion (54) of the yarn portion (14) are fixedly received in the receiving groove (52), and a second portion (58) of the yarn portion (14 ) abuts at least partially on the shaft (50) or a bearing inner ring (36). By the loop-like and flexible equipotential bonding element (10) a maintenance and low-friction electrical equipotential bonding within the rolling bearing assembly (30) is effective, whereby damage due to induced voltages are reliably prevented.

Description

The invention relates to a rolling bearing assembly having a rolling bearing and a potential equalization element, wherein the rolling bearing for supporting a shaft has at least one bearing outer ring and rolling rolling elements on this.

Rolling bearings are widely used in almost all areas of technology for the low-friction and low-maintenance storage of machine elements. Due to the high rotational speeds of rolling bearings in asynchronous electrical voltages can be induced, which must be derived via the rolling bearing. In an uncontrolled dissipation of the electrical voltage across the bearing rings and the rolling elements it comes with decreasing insulation effect of a rolling bearing possibly present lubricant in the careers often undesirable career damage.

For the derivation of such induced electrical voltages, among other things, bearing protection rings are known from the prior art. In this context, bearing protection rings are to be mentioned, for example, which are mounted in front of a roller bearing, and which derive the electrical voltages that may occur with the aid of circumferentially distributed carbon fiber brushes. A disadvantage of these known bearing protection rings is that the carbon fiber brushes can become dirty, which is accompanied by a reduction in the electrical discharge capability. Furthermore, the radially mounted brushes have no active adjustment functionality to compensate for their friction-related wear automatically.

In addition, electrically conductive nonwovens are known, which can be attached, for example, to a radial shaft seal and allow a defined passage of current through a so equipped rolling bearing. The disadvantage in this context is the increased axial space requirement and the hardly given Selbstjustierungsfähigkeit the conductive components.

The invention therefore an object of the invention to present a rolling bearing assembly with a low-maintenance and at the same time spatially compact equipotential bonding.

The solution of this problem is achieved with a roller bearing assembly having the features of claim 1. Advantageous developments are mentioned in the dependent claims.

Accordingly, the invention relates to a rolling bearing assembly with a rolling bearing and a potential equalization element, wherein the rolling bearing for supporting a shaft has at least one bearing outer ring and rolling rolling elements on this. To achieve the object, it is provided that a circular arc-shaped, radially outwardly open receiving groove is formed on the bearing outer ring, that the equipotential bonding element is elastic and loop-like that the equipotential bonding element comprises an elastomeric section and an electrically conductive yarn section that the elastomeric section and a first Area of the yarn section are received in the receiving groove stationary, and that a second region of the yarn section rests at least partially on the shaft or on a bearing inner ring

This rolling bearing arrangement allows for effective electrical voltage compensation between the bearing outer ring or a housing receiving this and a shaft. Due to the longitudinal elastic elastomer section, a sufficiently high mechanical preload of the equipotential bonding element in the circumferential direction is always ensured, which ensures good electrical contacting. In addition, the elastomer portion compensates for any slight abrasion in the region of the yarn portion and / or the shaft. The yarn section can be realized, for example, from an electrically conductive, stretch-torn carbon fiber yarn or a band-shaped fiber structure or fiber strands constructed, for example, from electrically conductive carbon fibers or the like.

The equipotential bonding element is easy to install and allows low electrical contact resistance. There is no functional impairment due to an accumulation of dirt and the mechanical wear is negligible. Furthermore, due to the length elasticity of the elastomeric portion of the equipotential bonding element, any shaft eccentricity and / or a possibly existing bearing play can be compensated. In addition, the elastically stretchable elastomer section allows for automatic readjustment in the event of possibly minor, wear-related geometry changes.

The yarn section of the equipotential bonding element is mechanically resistant even at comparatively high temperatures due to the carbon fibers preferably used. Damage to the rolling body raceway due to spark-induced scoring and / or cratering is reliably prevented by the equipotential bonding element of the rolling bearing arrangement according to the invention. In addition, the equipotential bonding element is practically maintenance-free for the duration of use.

According to a technically advantageous embodiment, it is provided that the elastomer section in the receiving groove has an arc length between 10 ° and 270 °, preferably between about 20 ° and 180 °. As a result, a sufficiently high mechanical bias of the equipotential bonding element and at the same time a reliable seat of the same in the receiving groove are given.

Preferably, an electrical contact area between the electrically conductive yarn section and the shaft or the inner ring of the rolling bearing has an enclosure length between about 15 ° and 340 °, preferably between 45 ° and 90 °. As a result, a reliable electrical contact is given at the same time minimized friction.

According to another advantageous embodiment, it is provided that the equipotential bonding element is formed reversibly separable. For this purpose, it has, for example, a plug connection. This simplifies the installation of the equipotential bonding element in difficult installation situations.

• 1 eine schematische Draufsicht auf ein erfindungsgemäßes Potentialausgleichselement,
• 2 eine axiale Draufsicht mit einer daneben dargestellten Seitenansicht einer aus einem Wälzlager und dem Potentialausgleichselement gemäß 1 gebildeten Wälzlageranordnung zusammen mit einer zu lagernden Welle, und
• 3 die Lageranordnung gemäß 2 mit einer exzentrisch angeordneten Welle.

For a better understanding of the invention, the description is accompanied by a drawing. In this drawing shows

• 1 a schematic plan view of an inventive potential equalization element,
• 2 an axial plan view with an adjacent side view of a rolling bearing and the equipotential bonding element according to FIG 1 formed rolling bearing assembly together with a shaft to be supported, and
• 3 the bearing assembly according to 2 with an eccentrically arranged shaft.

This in 1 shown, loop-like equipotential bonding element 10 Here, by way of example only, has a circular shape. It consists of a stretchable elastomer section 12 and an associated electrically conductive yarn section 14 , The elastomer section 12 extends over an arc length α between 10 ° and 270 °, but is preferably between 20 ° and 180 °, including the interval limits. Both the elastomer section 12 as well as the electrically conductive yarn section 14 are at least essentially limp.

The electrically conductive yarn section 14 is suitably in a first interface zone 16 and a second interface zone 18 for the formation of the loop-like self-contained geometry of the equipotential bonding element 10 with the elastomeric section 12 connected. The connection between the elastomer section 12 and the yarn section 14 in the area of the two interface zones 16 . 18 For example, irreversible, such as by pressing, welding, gluing, scorching etc. take place. Alternatively, an irreversible connection by means of at least one graphically indicated only connector 20 be provided. Depending on whether the connector 20 in the elastomeric section 12 or in the electrically conductive yarn section 14 is arranged, is the reversible plug-in connector 20 even carried out electrically conductive or insulating.

The electrically conductive yarn section 14 For example, it may be made of carbon fibers, derivatives of carbon fibers, metallic fibers, by means of polymer fibers (conductive plastics) made electrically conductive by means of suitable fillers, or the like. Particularly advantageous, the yarn section 14 from an electrically conductive, stretch-broken carbon fiber yarn or from an electrically conductive, ribbon-shaped, stretched-open carbon fiber yarn, which is formed, for example, from a plurality of axially adjacent carbon fiber strands.

Preferably comes for the yarn section 14 a stretch-broken carbon fiber yarn which has the highest possible tensile strength and a high elastic modulus. For example, such yarns achieve a tensile strength of 4.0 GPa, a tensile modulus of elasticity of 240 GPa, a breaking elongation of 1.7% with a resistivity of about 15 μΩm.

The elastomer section 12 For example, it may be formed from or with a rubber material or made from or with a silicone. The elastomer section 12 of the equipotential bonding element 10 isolated as a rule electrically and therefore has a negligible electrical conductivity.

2 shows an axial plan view and a side view of a rolling bearing 32 and the equipotential bonding element 10 according to 1 formed rolling bearing assembly 30 together with a shaft to be stored 50 , The rolling bearing arrangement 30 includes a rolling bearing 32 , which is merely a ball bearing here by way of example, as well as the equipotential bonding element 10 according to 1 , The rolling bearing 32 has an at least substantially hollow cylindrical bearing inner ring 36 on, which is coaxially surrounded by a likewise at least substantially hollow cylindrical bearing outer ring 38. Between the bearing inner ring 36 and the bearing outer ring 38 are spherical rolling elements 40 arranged, which on said bearing rings 36 . 38 roll. The rolling bearing 32 is rotationally symmetric to a longitudinal central axis 44 the rolling bearing assembly 30 educated. In the bearing inner ring 36 is a means the rolling bearing assembly 30 to be stored, cylindrical shaft 50 rotatable about the longitudinal central axis 44 added. Notwithstanding the embodiment of the rolling bearing shown here 32 the potential equalization element according to the invention can also be used in a roller bearing without a bearing inner ring, such as a needle sleeve or the like.

At the bearing outer ring 38 is for fixing the equipotential bonding element 10 an at least substantially circular arc-shaped receiving groove 52 formed with an approximately rectangular cross-sectional geometry. The receiving groove 52 is designed to be open at least radially outward. But it is also possible that this has a radially outward and axially outwardly open geometry in terms of a frontal paragraph. In the illustrated embodiment of 2 lies the elastomeric section 12 of the equipotential bonding element 10 completely in the receiving groove 52 ,

Furthermore, a first area 54 of the electrically conductive yarn section 14 in the receiving groove 52 of the bearing outer ring 38 completely absorbed, being between the first area 54 and the receiving groove 52 of the bearing outer ring 38 a first circular arc-shaped electrical contact region 56 to create a very good electrically conductive connection between the bearing outer ring 38 and the yarn section 14 of the equipotential bonding element 10 arises. At the first area 54 closes counterclockwise at least partially circular arc-shaped second area 58 of the electrically conductive yarn section 14 on, outside the receiving groove 52 runs and in a second circular arc-shaped electrical contact area 60 on the shaft 50 abuts so that between the yarn section 14 and the wave 50 a further electrically conductive connection is formed.

Between the elastomer section 12 and the yarn section 14 of the equipotential bonding element 10 and the receiving groove 52 Generally, there is no relative movement. A relative movement between the yarn section associated with frictional effects 14 and the wave 50 takes place only in the region of the second electrical contact region 60 when the wave 50 rotated with respect to the stationary bearing outer ring 38 or vice versa, when the bearing outer ring 38 around the stationary wave 50 rotates, which is then effective as a housing-fixed axis.

The enclosure length β of the second electrical contact region 60 can in this case depending on the geometric conditions of the bearing inner ring 36 , the bearing outer ring 38 as well as the wave 50 be in a range between 15 ° and 340 °, but it is preferably about 45 ° to 90 ° with respective inclusion of the interval limits, to frictional effects between the shaft 50 and the yarn section 14 to keep small at the same time as low as possible electrical contact resistance. Optionally, the yarn section 14 of the equipotential bonding element 10 the wave 50 even completely or once completely wrap around. Alternatively, the second area 58 of the yarn section 14 around the corresponding axially extended bearing inner ring 36 of the rolling bearing 32 be guided.

At the second, at least partially circular arc-shaped area 58 closes counterclockwise a third area 62 of the yarn section 14 which is completely in the receiving groove 52 the bearing outer ring 38 extends, and the third circular arc-shaped electrical contact area 64 to provide a further electrically conductive connection between the bearing outer ring 38 and the yarn section 14 of the equipotential bonding element 10 creates.

The elastically stretchable elastomer section 12 in this case guarantees a circumferential mechanical tensile stress, which is a reliable connection in the mentioned electrical contact areas 56 . 60 . 64 ensures. In addition, the elastomer section compensates 12 automatically any wear or abrasion in the region of the electrically conductive Garnabschnitts 14 and / or the wave 50 ,

With the help of the equipotential bonding element 10 is a low-resistance or good conductive electrical connection between the rotating in the rolling bearing assembly 30 recorded wave 50 and in a machine component 70 used bearing outer ring 38 of the rolling bearing 32 provided. In the machine component 70 it may be, for example, a bearing plate of an electric machine, not shown, or the like. Maybe in the wave 50 induced electrical voltages are thus reliable over the equipotential bonding element 10 on the bearing outer ring 38 or in the grounded machine component 70 derived, so that damage, especially a scoring and / or cratering in the region of the raceways of the bearing rings of the bearing 32 due to induced voltages is reliably avoided.

3 shows the rolling bearing assembly according to 2 with a shaft arranged eccentrically here 50 , The elastomer section 12 of the equipotential bonding element 10 runs completely in the receiving groove 52 of the bearing outer ring 38 of the rolling bearing 32 , here for the sake of better graphical clarity with only one rolling element 40 is shown. The three areas 54 . 58 . 62 of the electrically conductive yarn section 14 in turn form the three each at least substantially circular arc-shaped electrical contact areas 56 . 60 . 64 out. As a result, a reliable electrical contact between the bearing outer ring 38 and the shaft 50 given. The second area 58 of the yarn section 14 here has a central circular arc section 80 and a first straight line section 82 and a second straight line section 84 on, on both sides of the central circular arc section 80 connect.

In contrast to the representation according to 2 is the longitudinal center axis 86 the rolling bearing assembly 30 here, as with the arrow 88 indicated, off-center or eccentric to the original longitudinal central axis 44 the rolling bearing assembly 30 positioned. Due to the stretchable elastomer section 12 of the equipotential bonding element 10 This is without prejudice to the eccentricity of the shaft 50 by means of the equipotential bonding element 10 a consistently low-resistance electrical connection between the shaft 50 and the bearing outer ring 38 with the receiving groove formed thereon 52 of the rolling bearing 32 ensured.

Using the equipotential bonding element 10 is inside the rolling bearing assembly 30 always a low-friction and virtually maintenance-free and reliable electrical connection between the usually together with the bearing inner ring 36 rotating shaft 50 and then in relation to these components stationary and in the machine component 70 recorded bearing outer ring 38 of the bearing 32 the rolling bearing assembly 30 given.

LIST OF REFERENCE NUMBERS

10

Potential compensation element

12

elastomer section

14

Electrically conductive yarn section

16

First interface zone

18

Second interface zone

20

connector

30

roller bearing assembly

32

roller bearing

36

Bearing inner ring

38

Bearing outer ring

40

rolling elements

44

Longitudinal central axis

50

wave

52

receiving groove

54

First area of the yarn section

56

First electrical contact area

58

Second area of the yarn section

60

Second electrical contact area

62

Third area of the yarn section

64

Third electrical contact area

70

machine part

80

Arc section

82

First straight section

84

Second straight section

86

Longitudinal central axis

88

arrow

α

arc length

β

Umfassungslänge

Claims (4)

Rolling bearing assembly (30) with a roller bearing (32) and an equipotential bonding element (10), wherein the rolling bearing (32) for supporting a shaft (50) at least one bearing outer ring (38) and on this rolling rolling elements (40), characterized in that on the bearing outer ring (38) a circular arc-shaped, radially outwardly open receiving groove (52) is formed, that the equipotential bonding element (10) is elastic and loop-like, that the equipotential bonding element (10) has an elastomeric portion (12) and an electrically conductive yarn portion (14 ), that the elastomer portion (12) and a first portion (54) of the yarn portion (14) are received in the receiving groove (52) stationary, and that a second portion (58) of the yarn portion (14) at least partially on the shaft ( 50) or a bearing inner ring (36). Rolling arrangement after Claim 1 , characterized in that the elastomeric portion (12) extends in the receiving groove (52) over an arc length (a) between 10 ° and 270 ° or between 20 ° and 180 °. Rolling arrangement after Claim 1 or 2 , characterized in that an electrical contact region (60), in which the electrically conductive yarn portion (14) on the shaft (50) or on the bearing inner ring (36) is applied over an enclosure length (β) between about 15 ° and 340 ° or extending between 45 ° and 90 °. Rolling bearing assembly according to one of Claims 1 to 3 , characterized in that the equipotential bonding element (10) has a plug connection (20) by means of which the equipotential bonding element (10) is reversibly separable.

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