RADIAL ROLLING BEARING COMPRISING A DISCHARGE DEVICE AND METHOD FOR DISCHARGING ELECTROSTATIC CHARGES ON SUCH A RADIAL ROLLING BEARING

Description

[0001] The invention relates to a radial rolling bearing comprising a dissipation device and a method for dissipating electrostatic charges on such a rolling bearing.

[0002] Rolling bearings of the type mentioned above are well known in the art. For example, rolling bearings can have discharge devices formed by a device arranged adjacent to the rolling bearing. A disadvantage here is that such devices require a relatively large installation space, which is often not available around the rolling bearing.

[0003] Alternatively, the discharge device can comprise a flexible conductor that is clamped between the first and second bearing rings, forming a preload, so that the discharge device does not protrude from the rolling bearing and thus does not require additional installation space. The conductor must have a curved shape, for example a U-shape, V-shape, wave shape, spiral shape, or the like, with which the conductor bridges a space between the bearing rings when contacting them. Inserting the conductor into the rolling bearing necessarily occurs with the formation of a preload on the conductor, which is suitable for firmly holding the conductor to the rolling bearing.

[0004] The disadvantage here is that each conductor must be manufactured to fit the corresponding rolling bearing and must also have a correspondingly relatively complex shape. The production of such a conductor is therefore particularly complex and therefore costly. A conductor that is made too large or too wide for the rolling bearing may not be clamped into the rolling bearing, making it impossible to dissipate electrostatic charge at the rolling bearing. A conductor that is made too small or too short for the rolling bearing, on the other hand, carries the risk of falling out and thus a loss of contact between the dissipation device and the rolling bearing during operation, which breaks off the dissipation of electrostatic charge at the rolling bearing. This carries a risk of damage to the rolling bearing due to undischarged stray currents.Conductors that are not manufactured to fit the rolling bearing precisely may also be installed in the bearing with excessive preload. Installing such an unsuitable discharge device can also make it easier for the conductor to pop out of the bearing, for example, due to excessive preload, which also results in a loss of contact with the bearing and prevents the discharge of electrostatic charges from the bearing.

[0005] From JP H04 8820 U, a rolling bearing with a discharge device having the features of the preamble of claim 1 is known. Further rolling bearings with a discharge device are shown in EP 3 228 890 A1 and WO2016 / 095959 A1.

[0006] It is therefore the object of the present invention to propose a rolling bearing comprising a discharge device and a method for discharging electrical currents at the rolling bearing, wherein the discharge device is simple and cost-effective to manufacture and can be securely mounted on the rolling bearing and at the same time enables reliable discharge of electrostatic charges at the rolling bearing.

[0007] This object is achieved by a rolling bearing having the features of claim 1 and a method having the features of claim 16.

[0008] The rolling bearing according to the invention comprises a discharge device, wherein the discharge device comprises at least one flexurally elastic conductor, wherein the conductor has a first conductor section and a second conductor section for forming a contact arrangement on the rolling bearing, wherein the first conductor section is applied to a first bearing ring of the rolling bearing and the second conductor section is applied to a second bearing ring of the rolling bearing, wherein an electrically conductive connection is established between the first bearing ring and the second bearing ring by means of the conductor, wherein the rolling bearing is a radial bearing, and wherein the first bearing ring is an outer ring and the second bearing ring is an inner ring, wherein the first conductor section is an outer conductor section for contacting the outer ring of the radial bearing and the second conductor section is an inner conductor section for contacting the inner ring of the radial bearing, wherein the conductor is held on the outer ring,wherein the conductor with the first conductor section is inserted into at least one straight recess of the outer ring, wherein the straight recess is formed as a groove on at least one end face of the outer ring, or wherein the first bearing ring is an inner ring and the second bearing ring is an outer ring, wherein the first conductor section is an inner conductor section for contacting the inner ring of the radial bearing and the second conductor section is an outer conductor section for contacting the outer ring of the radial bearing, wherein the conductor is held on the inner ring, wherein the conductor with the first conductor section is inserted into at least one straight recess of the inner ring, wherein the straight recess is formed as a groove on at least one end face of the inner ring.

[0009] In the rolling bearing according to the invention, the discharge device is particularly simple in design, wherein the conductor is not clamped between the bearing rings of the rolling bearing and therefore does not have to have a complex shape. Instead, the invention provides that the conductor is fixed to the first bearing ring, wherein the first conductor section of the conductor is inserted into a correspondingly shaped recess in the first bearing ring. The second conductor section, which, however, is not held in a recess, then contacts the second bearing ring of the rolling bearing, wherein the second conductor section can be relatively freely movable on the second bearing ring. The arrangement of the discharge device on the rolling bearing can be such that the conductor does not touch the rolling elements and thus the functionality of the rolling bearing is not impaired by the discharge device.According to the invention, the recess is straight-shaped and designed as a groove. The recess is then particularly easy to form and can also be easily retrofitted to the rolling bearing after it has been manufactured. Furthermore, it is conceivable that not just one recess but a plurality of recesses can be formed on one or both bearing rings of the rolling bearing, which on the one hand enable a flexible arrangement of a conductor on the rolling bearing and on the other hand also enable the arrangement of two or more conductors of the same discharge device on the rolling bearing. It is essential that the conductor does not need to become jammed between the bearing rings, thus minimizing the risk of the conductor jumping out during operation of the rolling bearing.

[0010] Advantageously, the recess can be shaped to match the conductor. The recess is then designed to match the corresponding conductor cross-section, so that only a conductor suitable for discharging correspondingly large currents at the rolling bearing can be inserted and provided within the recess. The recess can have a cylindrical or partially cylindrical shape, but other shapes of the recess are also conceivable, which are suitable for receiving a corresponding conductor of the discharge device. Furthermore, it is conceivable for the recess to be designed in the form of a wedge or as a wedge-shaped groove, so that the recess can accommodate conductors of different diameters and, for example, enables the conductor to be clamped or fixed in the recess.

[0011] The conductor can be inserted into the recess in a force-fitting, form-fitting, and / or cohesive manner. The conductors can be clamped, wedged, or otherwise fastened to the recess in a force-fitting and / or cohesive manner when inserted into the recess. Furthermore, or alternatively, the conductor can be glued, soldered, or otherwise cohesively connected to the bearing ring in the region of the recess. By fastening the conductor to the first bearing ring in this way in the region of the recess, the conductor can be effectively prevented from falling out of the recess, thus reliably ensuring the functionality of the discharge device.

[0012] It is advantageous if the conductor is formed as a carbon fiber arrangement made of a braided carbon fibers, wherein the carbon fiber arrangement can be infiltrated with pyrolytic carbon. Such conductors are easy to manufacture and can be produced cost-effectively in large quantities. Dry lubrication in the contact area can also be achieved by forming the conductor from a carbon fiber arrangement. Furthermore, by infiltrating the carbon fiber arrangement with pyrolytic carbon, the conductor can be given dimensional stability, which can be customized during conductor manufacture by selecting the degree of infiltration.

[0013] The first conductor section can be formed by one end of the conductor, wherein the second conductor section can be formed by an opposite, free end of the conductor. In this case, the first conductor section is fastened to the first bearing ring, and contact is made between the second bearing ring and the second conductor section, which can be formed at an unfastened and therefore free end of the conductor. The conductor can be as long as the distance between the bearing rings of the rolling bearing requires, which distance must be bridged by the conductor. In this case, the free end of the conductor can make direct contact with the second bearing ring. Alternatively, the conductor can be longer than the distance to be bridged, so that it is not the free end directly that is provided for contacting the second bearing ring, but rather a section of the second conductor section that is slightly spaced apart from it.This contact can then be made tangentially to the second bearing ring.

[0014] Alternatively, the first conductor section can comprise two subsections at opposite ends of the conductor, wherein the subsections can each be inserted into recesses in the first bearing ring, wherein the second conductor section can be formed between the subsections inserted in the recesses. In this embodiment, both ends of the conductor are fixed in recesses in the first bearing ring such that a section lying between the ends of the conductor forms the second conductor section for contacting the second bearing ring. In this case, the first bearing ring can have at least two recesses for receiving the subsections of the first conductor section. By fastening the conductor at both ends in this way, a particularly stable fixation of the conductor to the first bearing ring can be achieved.Furthermore, since no free ends of the conductor directly contact the second conductor section, fraying of the conductor ends can be avoided. This can significantly extend the service life of a rolling bearing with such a conductor in the discharge device.

[0015] The conductor can advantageously be straight or curved. Conductors shaped in this way can be cut to the desired length easily, quickly, and in large quantities, for example, from a roll or strand. The conductors can, for example, have a carbon fiber arrangement or, alternatively, be formed as a wire, preferably made of a metal wire, such as a copper wire. After cutting, the conductor can be installed coated or uncoated directly in the rolling bearing.

[0016] It is also advantageous if a contact force can be exerted on the second bearing ring by means of the conductor. The conductor can be flexible or elastic and arranged on the rolling bearing in such a way that the conductor generates the contact force. The contact force can, for example, be exerted in the form of a spring force of the conductor, which arises because the conductor acts as a leaf spring within the rolling bearing due to its stability or elasticity. By exerting the contact force, a loss of contact between the conductor attached to the first bearing ring and the second bearing ring can be avoided.

[0017] In addition, the contact force can be brought about by prestressing the conductor, wherein the conductor can be arranged on the bearing rings so that the prestress is formed. In this case, it can be provided that the recess is designed such that it aligns the conductor in the direction of the second bearing ring to form the prestress. A corresponding angle of the straight-shaped recess on the first bearing ring can be set so that it does not correspond to the angle of a simple application of the conductor to the second bearing ring. It is important that the conductor is prestressed after being arranged on the rolling bearing, i.e. after being inserted into the recess in the first bearing ring and applied to the second bearing ring, which is achieved, for example, by slightly bending the conductor. Due to the prestress, the conductor can then exert the contact force on the second conductor section on the second bearing ring.This in turn ensures that the conductor makes secure contact with the bearing rings of the rolling bearing.

[0018] According to the invention, the rolling bearing is a radial bearing, wherein the first conductor section is an outer conductor section for contacting an outer ring of the radial bearing and the second conductor section is an inner conductor section for contacting an inner ring of the radial bearing, or vice versa. The conductor is held on the outer ring or on the inner ring, and the conductor with the first conductor section is inserted into at least one recess in the outer ring or the inner ring. A radial bearing is understood here to be a deep groove ball bearing, an angular contact ball bearing, a four-point contact bearing, a shoulder ball bearing, a self-aligning ball bearing, a cylindrical roller bearing, a tapered roller bearing, a spherical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a spherical roller bearing, or a clamping ring bearing.

[0019] In this case, an outer circumference of the inner ring or an inner circumference of the outer ring can be contacted by means of the second conductor section, wherein the second conductor section can be applied to a radial groove in the inner ring or the outer ring. The second conductor section can then be movably arranged on the outer circumference of the inner ring or the inner circumference of the outer ring, but can be fixed in the direction of the bearing axis by the groove. The groove can be shaped to match the conductor. By designing the groove to match the shape of the conductor, slipping or slipping out of the groove of the conductor section can be effectively prevented. The second conductor section can also be applied to the groove with the second conductor section either at one end of the conductor or at a section between the ends of the conductor.

[0020] The conductor can be arranged tangentially to the inner ring and / or secantially to the outer ring. If the conductor is arranged tangentially to the inner ring, the second conductor section of the conductor can be arranged tangentially to the inner ring, whereby the first conductor section of the conductor can be held on the outer ring. Alternatively, the second conductor section of the conductor can be arranged secantially to the outer ring, whereby the first conductor section of the conductor can then be held on the inner ring.

[0021] According to the invention, the recess is formed as a groove on at least one end face of the outer ring or the inner ring. Furthermore, two or more recesses can be formed on one end face of the outer ring or the inner ring. The recesses can also be arranged on one or both end faces of the outer ring or inner ring. The recesses can be formed as a groove. It is essential that the recess is straight and thus does not run radially to the bearing axis on the outer ring or inner ring.

[0022] Advantageously, the discharge device can comprise two or more conductors in a conductor arrangement, wherein the first conductor sections of the conductors can each be inserted into recesses in the first bearing ring. The first bearing ring can then have a corresponding number of recesses for fastening the conductors to the first bearing ring. In this case, it is conceivable that initially only one conductor can be inserted into one of the recesses and, if necessary, one, two or more further conductors can be inserted into recesses in the first bearing ring. Several conductors can also be fastened to the first bearing ring at the same time. In this case, assembly of the conductors can take place by inserting the first conductor sections into recesses in the first bearing ring, which makes assembly of the discharge device very simple.In addition, the use of two or more conductors in a conductor arrangement can significantly reduce the risk of damage to the rolling bearing due to stray currents, since even if one conductor wears out or falls out, at least one other functional conductor is available to dissipate electrostatic charges on the rolling bearing.

[0023] The conductors can be identically designed and arranged on the bearing rings with rotational symmetry relative to the bearing axis of the rolling bearing. If the conductors of the discharge device are identically designed, they can be manufactured particularly easily and cannot be confused or incorrectly fastened during assembly on the bearing rings of the rolling bearing. Such simplified assembly also increases the safety of the rolling bearing during operation, as contact between the bearing rings is always guaranteed using identically designed conductors. The fact that the conductors can be arranged rotationally symmetrically on the bearing rings also ensures uniform contact between the bearing rings of the rolling bearing and thus uniform discharge of electrical currents.

[0024] In addition, the conductors can be arranged axially symmetrically on the bearing rings with respect to a diameter of the bearing rings. This can be the case if the first conductor section has two subsections, each of which can have recesses inserted into the first bearing rings, so that the second conductor section can be formed on the conductor between the subsections inserted into the recesses.

[0025] Alternatively, the conductors can be arranged axially asymmetrically on the bearing rings with respect to a diameter of the bearing rings. In this case, the conductors can be fixed to the first bearing ring at only one end, so that a free end can form the second conductor section.

[0026] The method according to the invention serves to dissipate electrostatic charge on a rolling bearing, wherein the rolling bearing comprises a dissipation device with at least one flexurally elastic conductor, wherein the conductor is formed with a first conductor section and a second conductor section to form a contact arrangement on the rolling bearing, wherein the first conductor section is applied to a first bearing ring of the rolling bearing and the second conductor section is applied to a second bearing ring of the rolling bearing, wherein the conductor establishes an electrically conductive connection between the first bearing ring and the second bearing ring, wherein the conductor is held on the first bearing ring, wherein the first conductor section is inserted into at least one straight-shaped recess of the first bearing ring, wherein the rolling bearing is a radial bearing,The first conductor section is an outer conductor section for contacting an outer ring of the radial bearing, and the second conductor section is an inner conductor section for contacting an inner ring of the radial bearing. The conductor is held on the outer ring or the inner ring. The conductor, with the first conductor section, is inserted into at least one recess in the outer ring or the inner ring, the recess being formed as a groove on at least one end face of the outer ring or the inner ring. Regarding the advantageous effects of the method according to the invention, reference is made to the description of the advantages of the rolling bearing according to the invention. Advantageous embodiments of the method emerge from the feature descriptions of the subclaims referring back to device claim 1.

[0027] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings.

[0028] They show: Fig. 1 A perspective view of a rolling bearing in a first embodiment; Fig. 2 a perspective view of a rolling bearing in a second embodiment.

[0029] Fig. 1 shows a rolling bearing 10 in the form of a ball bearing 11, which comprises a first bearing ring 12 and a second bearing ring 13 as well as rolling elements 14 arranged between the bearing rings 12, 13. The first bearing ring 12 is an outer ring 15 of the rolling bearing 10, and the second bearing ring 13 is an inner ring 16 of the rolling bearing 10. The rolling bearing 10 further comprises a discharge device 17, wherein the discharge device 17 comprises two conductors 18 in a conductor arrangement 19. The conductors 18 are designed as a carbon fiber arrangement 20, wherein the carbon fiber arrangement 20 is infiltrated with pyrolytic carbon. The conductors 18 each have a first conductor section 21 and a second conductor section 22 for forming a contact arrangement 23 on the rolling bearing 10. The first conductor section 21 is formed by an end 24 of a conductor 18, wherein the end 24 is inserted into a straight recess 25 of the first bearing ring 12.An opposite end 26 of the conductor 18 forms the second conductor section 22, wherein the end 26 of the conductor 18 is inserted into a radial groove 27 of the second bearing ring. The second conductor section 22 is movably arranged within the groove 27, whereas the first conductor section 21 is firmly fixed in the recess 25. Through this arrangement of the conductor sections 21, 22, an electrically conductive connection can be established between the bearing rings 12, 13 by means of the conductor 18, whereby electrostatic charges on the rolling bearing 10 can be dissipated without requiring additional installation space around the rolling bearing 10.

[0030] In contrast to Fig. 1 shows Fig. 2a rolling bearing 28 with a discharge device 29, wherein the discharge device 29 comprises two conductors 30 in a conductor arrangement 31, wherein the conductors 30 are each inserted at opposite ends 32 of the conductors 30 into recesses 33 of a first bearing ring 34 of the rolling bearing 28. As a result, a first conductor section 35 of each conductor 30 is formed by two partial sections 36 at the opposite ends 32 of the conductor 30. A second conductor section 37 of the conductor 30 is formed between the partial sections 36 of the conductor 30. Here, too, the second conductor section 37 is placed in a groove 38 of a second bearing ring 39 of the rolling bearing 28. The second conductor section 37 is also arranged to be movable within the groove 38, whereas the partial sections 36 of the first conductor section 35 are fixed in the recesses 33.

Claims

1. A roller bearing (10, 28) comprising a conduction apparatus (17, 29), the conduction apparatus comprising at least one elastic conductor (18, 30), the conductor having a first conductor section (21, 35) and a second conductor section (22, 37) for forming a contact assembly (23) on the roller bearing, the first conductor section being mounted on a first bearing ring (12, 34) of the roller bearing and the second conductor section being mounted on a second bearing ring (13, 39) of the roller bearing, an electrically conductive connection being established between the first bearing ring and the second bearing ring by means of the conductor, the roller bearing being a plain bearing, and: a) the first bearing ring is an outer ring (15) and the second bearing ring is an inner ring (16), the first conductor section being an outer conductor section for establishing contact with the outer ring (15) of the plain bearing and the second conductor section being an inner conductor section for establishing contact with an inner ring (16) of the plain bearing, the conductor being supported at the outer ring, the conductor being inserted in at least one straight recess (25, 33) of the outer ring by its first conductor section, characterized in that the straight recess is realized as a groove on at least a front face of the outer ring or b) that the first bearing ring inner ring (15) and the second bearing ring is an outer ring (16), the first conductor section being an inner conductor section for establishing contact with the inner ring (15) of the plain bearing and the second conductor section being an outer conductor section for establishing contact with an outer ring (16) of the plain bearing, the conductor being supported at the inner ring, the conductor being inserted in at least one straight recess of the inner ring by its first conductor section, characterized in that the straight recess is realized as a groove on at least a front face of the inner ring.

2. The roller bearing according to claim 1, characterized in that the recess (25, 33) is formed so as to conform with the conductor (18, 30).

3. The roller bearing according to claim 1 or 2, characterized in that the conductor (18, 30) is inserted into the straight recess (25, 33) in a force-fit, form-fit or substance-to-substance bonded manner.

4. The roller bearing according to any one of the preceding claims, characterized in that the conductor (18, 30) is realized as a carbon fiber assembly (20) made of a braid of carbon fibers, the carbon fiber assembly being infiltrated with pyrolytic carbon.

5. The roller bearing according to any one of the preceding claims, characterized in that the first conductor section (21) is formed by an end (24) of the conductor (18), the second conductor section (22) being formed by an opposite, free end (26) of the conductor.

6. The roller bearing according to any one of the claims 1 to 4, characterized in that the first conductor section (35) comprises two partial sections (36) on opposite ends (32) of the conductor (30), the partial sections each being inserted in the straight recesses (33) of the first bearing ring (34), the second conductor section (37) being formed between the partial sections inserted in the recesses.

7. The roller bearing according to any one of the preceding claims, characterized in that the conductor (18, 30) is straight or curved.

8. The roller bearing according to any one of the preceding claims, characterized in that a contact force is exerted on the second bearing ring (13, 39) by means of the conductor (18, 30).

9. The roller bearing according to claim 8 the contact force is caused by prestressing the conductor (18, 30), the conductor being disposed on the bearing rings (12, 13, 34, 39) by producing the prestressing.

10. The roller bearing according to any one of the preceding claims, characterized in that an outer periphery of the inner ring (16) or an inner periphery of the outer ring (15) is contacted by means of the second conductor section (22, 37), the second conductor section being supported on a radial groove (27, 38) of the inner ring or the outer ring.

11. The roller bearing according to any one of the preceding claims, characterized in that the conductor (18, 30) is tangential to the inner ring (16) and / or secantial to the outer ring (15).

12. The roller bearing according to any one of the preceding claims, characterized in that the conduction apparatus (17, 29) comprises two or more conductors (18, 30) in a conductor assembly (19, 31), the first conductor sections (21, 35) of the conductors each being inserted in the straight recesses (25, 33) of the first bearing ring (12, 34).

13. The roller bearing according to claim 12, characterized in that the conductor (18, 30) is identical and is disposed on the bearing rings (12, 13, 34, 39) in a rotationally symmetric manner with respect to a bearing axis of the roller bearing (10, 28).

14. The roller bearing according to claim 12 or 13, characterized in that the conductor (30) is disposed on the bearing rings (34, 39) in an axially symmetric manner with respect to a diameter of the bearing rings.

15. The roller bearing according to claim 12 or 13, characterized in that the conductors (18) are disposed on the bearing rings (12, 13) in an axially symmetric manner with respect to a diameter of the bearing rings.

16. A method for conducting electrostatic charges at a roller bearing (10, 28), the roller bearing comprising a conduction apparatus (17, 29) comprising at least one elastic conductor (18, 30), the conductor being formed to have a first conductor section (21, 35) and a second conductor section (22, 37) for forming a contact assembly (23) on the roller bearing, the first conductor section being mounted on a first bearing ring (12, 34) of the roller bearing and the second conductor section being mounted on a second bearing ring (13, 39) of the roller bearing, the conductor establishing an electrically conductive connection between the first bearing ring and the second bearing ring, the roller bearing being a plain bearing, and: a) the first bearing ring is an outer ring (15) and the second bearing ring is an inner ring (16), the first conductor section being an outer conductor section for establishing contact with the outer ring (15) of the plain bearing and the second conductor section being an inner conductor section for establishing contact with an inner ring (16) of the plain bearing, the conductor being supported at the outer ring, the conductor being inserted in at least one straight recess (25, 33) of the outer ring by its first conductor section characterized in that the straight recess is realized as a groove on at least a front face of the outer ring or b) that the first bearing ring inner ring (15) and the second bearing ring is an outer ring (16), the first conductor section being an inner conductor section for establishing contact with the inner ring (15) of the plain bearing and the second conductor section being an outer conductor section for establishing contact with an outer ring (16) of the plain bearing, the conductor being supported at the inner ring, the conductor being inserted in at least one straight recess of the inner ring by its first conductor section, characterized in that the straight recess is realized as a groove on at least a front face of the inner ring.