Sealing device

Abstract

The invention relates to a sealing device having a sealing element with a carrier plate having a sealing body made of an elastomeric material molded thereon, the sealing body having at least a first sealing lip, the first sealing lip having a second sealing lip, and the second sealing lip having a second sealing lip. The elastomeric material of the sealing body is provided with fillers at least partially arranged therein, the elastomeric material having at least a first filler and a second filler different from the first filler, and particles of at least one of the fillers have a greater hardness than the elastomeric material of the sealing body.

Description

Technical Field

[0001] The present invention relates to a sealing device having a sealing element, the sealing element having a carrier plate, the carrier plate having a sealing body made of an elastomeric material molded thereon, the sealing body being provided with a filler at least partially disposed therein, and the sealing device being applicable to various applications, such as for bearings such as wheel bearings, wind turbines, e-mobility applications, agricultural machinery, processing machines, or for all applications including such a sealing device where dynamic seals are used. Background Art

[0002] DE 10 2018 132 388A1 discloses a seal having an elastomeric body. The elastomeric body at least partially has a special filler mixture. The elastomeric body is, for example, composed of a vulcanized elastomeric mixture or a thermoplastic elastomer containing a filler as a filler mixture. An example in this regard is the use of PTFE as an anti-friction substance, which is used as a filler in the seal. However, due to its rather soft surface and self-lubricating properties, this has the disadvantage of causing high wear on the seal. Summary of the Invention

[0003] The object of the present invention is to provide a sealing element and a bearing device having improved frictional properties, especially lower frictional losses in the seal lip contact, and wherein the wear of the seal should also be positively affected. This object is achieved by the subject matter of claim 1. Preferred embodiments can be found in the dependent claims, the description, and the drawings.

[0004] The sealing device according to the present invention has a sealing element, the sealing element having a carrier, the carrier having a sealing body made of an elastomeric material molded thereon, wherein the sealing body has at least a first sealing lip, wherein the elastomeric material of the sealing body is provided with a filler at least partially disposed therein, wherein the elastomeric material has at least a first filler and a second filler different from the first filler, and wherein the particles of at least one of the fillers have a higher hardness than the elastomeric material of the sealing body.

[0005] For example, the carrier can be a carrier plate made of a metallic material. Alternatively, the carrier can also be made of plastic, fiber composite material, etc.

[0006] By adding a combination of at least two different fillers, both the friction on the seal and the wear on the seal can be reduced. The filler with a higher hardness makes the seal more durable. Suitable fillers for the first filler or the second filler can be: glass, carbon, graphite, basalt, phenolic resin, and PTFE. It is also conceivable to add other anti-friction fillers, such as molybdenum disulfide, aramid, or bronze.

[0007] Using a suitable manufacturing method, the elastomeric material of the sealing body, in particular at least the first sealing lip, is at least partially enriched with a filler consisting of a plurality of fine particles, fibers or powders. Preferably, the entire seal contains a filler.

[0008] In principle, any basic elastomeric material is suitable for the sealing body. Nitrile rubber, such as NBR (nitrile butadiene rubber), is particularly suitable. It is also conceivable to use HNBR (hydrogenated nitrile butadiene rubber), FKM (fluorocarbon rubber), ACM (acrylate copolymer), EPDM (ethylene propylene diene (monomer) rubber), etc. Thermoplastic elastomers, such as TPE, TPU, TPA, etc., or even mixtures of the materials mentioned above can also be used.

[0009] In the mixing process of the elastomeric material, also known as the matrix compound, the filler can be added to the mixture in a simple manner such that no further manufacturing or processing steps of one or more components of the sealing element are required. The elastomeric mixture can also be used for a sealing device comprising a surface-modified counter-running surface, which can be expected to further reduce friction. In principle, the filler can be made of a material having a higher hardness than the elastomeric material, also known as the matrix compound. However, hard fillers can also be mixed with softer anti-friction fillers.

[0010] In a preferred embodiment, the first filler is made of carbon such as carbon fiber, carbon fiber fragments or carbon fiber particles. It is also conceivable that barium sulfate can be used as a filler. By adding a relatively hard filler, such as carbon fiber, phenolic resin, etc., the wear resistance of the seal can be improved, and the surface microstructure can also be positively affected. Friction is reduced by having the filler directly present in the frictional contact, where the filler reduces the friction of the seal due to its high hardness and low friction compared to rubber.

[0011] Preferably, the second filler is made of PTFE micropowder, glass powder and / or phenolic resin or a combination thereof. It is also conceivable to use barium sulfate, especially barium sulfate having a size in the range between 30 μm and 500 μm, as the second filler. By adding these fillers to the elastomeric material, the friction of the seal can be further reduced.

[0012] Advantageously, the filler variant, i.e., the particles of the first filler or the second filler, are softer than the material of the counter-running surface. The filler having such particles is particularly made of carbon or plastics such as PTFE, carbon fiber, thermoplastic or resin. This has the advantage that if the filler is released from the elastomeric material due to wear, etc., they will not damage the component or bearing unit to be sealed.

[0013] In a preferred exemplary embodiment, the elastomeric material of the seal is provided with particles of a third filler. The third anti-friction filler is preferably formed of glass powder and / or phenolic resin. Preferably, the elastomeric material is made of vulcanized rubber. For example, the vulcanized rubber can be nitrile rubber (NBR), acrylate rubber (ACM), or fluororubber (FKM). The combination of NBR as the elastomeric material, carbon fiber as the first filler, PTFE micropowder as the second filler, and glass powder as the third filler is particularly preferred in this context.

[0014] Preferably, the particles of the first filler and the particles of the second filler have different geometries. Preferably, the particles of the first filler are spherical or ellipsoidal and the particles of the second filler are fibrous, or the particles of the first filler are fibrous and the particles of the second filler are spherical or ellipsoidal, and the particles of the third filler are powdery. However, the same fillers can also be mixed in different geometries. It is also conceivable that the first filler, the second filler, and the third filler have the same geometry. For example, this may occur when using glass powder or carbon fiber powder as fillers.

[0015] In principle, the filler particles can have any shape or structure. The ellipsoidal, spherical, and / or fibrous shapes of the filler particles have proven to be advantageous. In other words, the filler is ellipsoidal, spherical, and / or fibrous particles. One advantage of spherical or ellipsoidal filler particles is that the filler can be very evenly distributed in the elastomeric material. Fibrous filler particles can additionally mechanically reinforce the elastomeric material. The combination of FKM as the elastomeric material and spherical or fibrous filler has particularly good frictional properties. Irregular particles, i.e., particles with an irregular shape, have the advantage of better interlocking with the polymer matrix compared to circular particles and can thus achieve better adhesion in the matrix. To improve the embedding in the elastomer, fibrous fillers are preferred. Additionally, the filler can also be provided with special surface treatments, such as sizing, surface activation, or functional groups. Thus, the particles can be designed to be regular and irregular spherical or ellipsoidal, etc.

[0016] During the manufacture of the sealing body, at least some of the spherical, ellipsoidal and / or fibrous filler particles can accumulate on the surface of the sealing body, in particular on the surface of at least the first sealing lip. These particles can protrude from the surface and at the same time be embedded in the elastomeric material, or they can be covered by a thin elastomeric layer. In the latter case, when the elastomer crosslinks and shrinks during manufacture, the elastomer stretches over the filler particles arranged on the surface. In both cases, the filler constitutes the surface of at least the first sealing lip. In this way, frictional losses on the surface of the sealing body or in the contact area between the sealing body and the running plate can be significantly reduced, without impairing the sealing effect. As the seal wears, the particles are exposed and reduce friction due to their higher hardness and possible additional anti-friction or self-lubricating properties.

[0017] For spherical or ellipsoidal particles, phenolic resin beads, glass beads, hollow glass beads, PE or HDPE beads with a diameter range of 5 μm to 200 μm are particularly suitable. Preferably, the spherical and / or ellipsoidal filler particles have a diameter between 10 μm and 50 μm. Phenolic resin beads, glass beads, PE or HDPE beads such as Mipelon are particularly advantageous as materials for spherical or ellipsoidal particles. Glass beads, hollow glass beads and beads made of PEEK, phenolic resin and epoxy resin have a relatively high electrical resistance.

[0018] The filler composed of spherical or ellipsoidal particles makes it easy to achieve a more uniform structure on the surface of the sealing body. For a more robust geometry of the sealing body or sealing element, particles with a larger diameter can also be used. The ellipsoidal particles are also preferably characterized in that the ratio of the diameter to the length is between 1:1 and 1:10, preferably between 1:1.1 and 1:1.5.

[0019] Fibrous particles of the above-mentioned filler with a diameter of 4 μm to 30 μm and a length of 50 μm to 1000 μm for the fibers remaining in the compound after the mixing process are considered advantageous. Glass, carbon and PTFE are particularly suitable due to their chemical inertness, as they exhibit a relatively high tolerance to lubricants. The combination of a hard filler and a filler with self-lubricating properties such as PTFE is particularly suitable when the thin elastomeric layer stretching over the filler particles arranged on the surface of the sealing body wears out, as they reduce friction even if the friction or contact surface between the sealing lip and the running plate increases due to wear.

[0020] Particularly preferably, the elastomeric material of the seal is provided with 1.5% to 15%, in particular 3% to 7%, of a first filler. The first filler is preferably carbon or carbon fiber.

[0021] In another embodiment, the elastomeric material is provided with a second filler in an amount of 1.5% to 15%, in particular 1% to 4%. The second filler is preferably PTFE fine powder. This combination of the first filler and the second filler in the seal allows for a friction-optimized and durable seal.

[0022] The third filler is preferably glass powder or phenolic resin particles. This combination of the first filler, the second filler and the third filler in the seal allows for a highly friction-optimized and durable seal.

[0023] Furthermore, the invention relates to a bearing comprising at least one outer ring and at least one inner ring, wherein at least one sealing device is spatially arranged between the respective inner ring and the respective outer ring, wherein the sealing device has a sealing element, the sealing element having a carrier, the carrier having a sealing body made of an elastomeric material molded thereon, wherein the sealing body has at least a first sealing lip, wherein the elastomeric material of the sealing body is provided with a filler at least partially arranged therein, wherein the elastomeric material has at least a first filler and a second filler, wherein the particles of at least one of the fillers have a higher hardness than the elastomeric material of the sealing body, and wherein a running plate is provided, the sealing lip sealingly contacting the running plate, wherein the carrier is arranged to be rotatable relative to the running plate, or the running plate is arranged to be rotatable relative to the carrier. The sealing device can be used in automobiles, trucks and all applications where seals are used under dynamic conditions, i.e., not only for sealing bearings.

[0024] The bearing is preferably a wheel bearing for a vehicle. Description of the Drawings

[0025] Further measures for improving the invention and a description of two preferred exemplary embodiments of the invention are described in more detail below with reference to the drawings, wherein the same or similar elements are provided with the same reference numerals. In the drawings:

[0026] Figure 1 A simplified schematic cross-sectional view of a wheel bearing according to the invention having two sealing devices is shown,

[0027] Figure 2 A schematic cross-sectional view of a first sealing device according to a first exemplary embodiment is shown,

[0028] Figure 3 A schematic cross-sectional view of a second sealing device of the wheel bearing according to a first exemplary embodiment is shown,

[0029] Figure 4 A schematic cross-sectional view of a first sealing device according to a second embodiment is shown, and

[0030] Figure 5 Shows a schematic cross-sectional view of a second sealing device according to a second embodiment. Detailed implementation

[0031] Figure 1 Shows an exemplary bearing 10 for a vehicle—not shown here—in this case a wheel bearing, which includes an outer ring 11 and two inner rings 12, 25. The first inner ring 12 is integrally connected to the hub 22. When the first inner ring 12 is mentioned hereinafter, this should be understood as the flange of the hub 22 on which a raceway is formed, and the rolling elements in the first row of rolling elements 23 of the bearing 10 roll on this raceway. In contrast, for construction reasons, the second inner ring 25 is pressed onto the hub 22. In the present case, two rows of rolling elements 23, 27 are spatially arranged between the outer ring 11 and the inner rings 12, 25. In addition, the interior 8 of the bearing 10 is sealed from the external region 9 by two sealing elements 1, 24. In Figure 2 and Figure 3 for the first exemplary embodiment and in Figure 4 and Figure 5 for the second exemplary embodiment, the detailed structures of the sealing elements 1, 24 are shown in more detail, wherein the sealing elements 1, 24 of different embodiments only differ in the design of the sealing body 3. Each sealing element 1, 24 has a carrier 2 and a running plate 4, wherein the carrier 2 of the corresponding sealing element 1, 24 is arranged on the outer ring 11 in a non-rotatable manner, and the running plate 4 of the corresponding sealing element 1, 24 is arranged on the first inner ring 12 or the second inner ring 25 in a non-rotatable manner. The carrier 2 is arranged, for example, to be rotatable relative to the running plate 4.

[0032] In the present case, the carrier 2 is designed with an L-shaped cross-section and has a substantially axial section 16 and a substantially radial section 17. The carrier 2 is pressed into the outer ring 11 by means of the axial section 16. The running plate 4 is designed with a C-shaped cross-section, wherein the corresponding running plate 4 is pressed into the first inner ring 12 or pressed onto the second inner ring 25 by means of the first substantially axial leg 20. As shown in Figure 3 and Figure 5 The running plate 4 may have a vulcanized coding ring—not described in detail here—which interacts with a sensor device—not shown here—to determine, for example, the rotational speed.

[0033] A sealing body 3 is vulcanized onto the carrier 2 of the corresponding sealing element 1, 24, which sealing body has an elastically deformable first sealing lip 5, a second sealing lip 18 and a third sealing lip 26, and each of the sealing lips extends at an angle from the sealing body 3 in the direction of the running plate 4. The first sealing lip 5 and the second sealing lip 18 are in sealing contact with a first reverse running surface 7 on the radial leg 19 of the running plate 4. RegardingFigure 2 and Figure 4 In the first sealing element 1 shown in Figure 3 , the third sealing lip 26 is in sealing contact with the second reverse running surface 21 on the second substantially axial leg 28 of the running plate 4. Regarding Figure 3 and Figure 5 In the second sealing element 24 shown in , the third sealing lip 26 is in sealing contact with the second reverse running surface 21 on the first substantially axial leg 20 of the running plate 4.

[0034] The sealing body 3 is designed as a sealing ring made of an elastomeric material, such as NBR, in which fillers 6a, 6b are arranged. In this regard, the elastomeric material is formed by a combination of at least two different fillers 6a, 6b.

[0035] The first filler 6a has substantially spherical particles 13 in a first exemplary embodiment according to Figures 1 to 3 and has substantially fibrous particles 14 in a second exemplary embodiment according to Figure 4 and Figure 5 The fillers 6a, 6b are arranged in a uniformly distributed manner throughout the elastomeric material of the sealing body 3, wherein some of the particles 13, 14 are arranged on the surface of the sealing body 3, in particular on the sealing lips 5, 18, 26 in contact with the running plate 4. The fillers 6a, 6b have a higher hardness than the elastomeric material of the sealing body 3 and have the effect of structuring the surface 15 of the sealing body 3 in the case where they are arranged on the surface 15. Due to the geometric shape and material-specific properties of the particles 13, 14 of the fillers 6a, 6b, the structuring of the surface 15 reduces the friction in the sealing lips in contact with the running plate 4, which reduces the torque in the bearing 10.

[0036] According to Figure 2 and Figure 3 , the particles 13 of the first fillers 6a, 6b are designed to be spherical. The spherical particles 13 can be made of plastic, elastomer, glass, carbon or ceramic. All or part of the particles 13 can also be designed to be ellipsoidal. Preferably, the first filler 6a is mixed into the sealing body 3 in a higher percentage than the second filler 6b. The first filler 6a is particularly preferably composed of carbon fibers. These fillers are preferably mixed into the elastomeric material of the sealing body 3 in an amount of 1.5% to 15%, particularly preferably 3% to 7%. The second filler 6b, which is different from the first filler, can have a different geometry.

[0037] In Figure 2 and Figure 3In this case, the second filler 6b is designed to be fibrous. Preferably, the second filler 6b consists of PTFE fine powder, glass powder or phenolic resin beads. The second filler 6b is preferably mixed into the elastomeric material of the sealing body 3 in an amount of 1.5% to 15%, particularly preferably 1% to 4%. Thus, a combination of two different fillers 6a, 6b is added to the sealing body 3, which can reduce both friction and wear on the seal.

[0038] According to Figure 4 and Figure 5 , the particles 14 of the first filler 6a are designed to be fibrous. The fibrous particles 14 can consist of carbon fiber, plastic, elastomer, glass, ceramic or a mixture of the foregoing. Carbon fiber is chemically inert, enabling improved chemical compatibility of the corresponding sealing elements 1, 24. In this exemplary embodiment, the particles of the second filler 6b are designed to be spherical. In this exemplary embodiment, the sealing body 3 is composed of an elastomeric material such as NBR, which is mixed with 1.5% to 15% of the first filler 6a, particularly carbon fiber, and 1.5% to 15% of the second filler 6b, preferably PTFE fine powder, glass powder or phenolic resin beads.

[0039] It is also conceivable to provide an elastomeric material for the sealing body 3 having a first filler, a second filler and a third filler. The third filler is particularly preferably composed of PTFE fine powder, glass powder or phenolic resin beads.

[0040] List of reference numerals

[0041] 1 First sealing element

[0042] 2 Carrier

[0043] 3 Sealing body

[0044] 4 Running plate

[0045] 5 First sealing lip

[0046] 6a First filler

[0047] 6b Second filler

[0048] 7 First reverse running surface

[0049] 8 Interior

[0050] 9 Outer region

[0051] 10 Bearing

[0052] 11 Outer ring

[0053] 12 First inner ring

[0054] 13 Spherical particle

[0055] 14 fibrous particles

[0056] 15 surface

[0057] 16 axial section of the bearing plate

[0058] 17 radial section of the bearing plate

[0059] 18 second sealing lip

[0060] 19 radial leg of the running plate

[0061] 20 first axial leg of the running plate

[0062] 21 second reverse running surface

[0063] 22 hub

[0064] 23 first row of rolling elements

[0065] 24 second sealing element

[0066] 25 second inner ring

[0067] 26 third sealing lip

[0068] 27 second row of rolling elements

[0069] 28 second axial leg of the running plate

Claims

1. A sealing device having a sealing element (1, 24), the sealing element having a carrier (2), the carrier having a sealing body (3) molded thereon made of an elastomeric material, the sealing body (3) having at least a first sealing lip (5), the elastomeric material of the sealing body (3) being provided with a filler (6a, 6b) at least partially disposed therein, characterized in that, The elastomeric material has at least a first filler (6a) and a second filler (6b) different from the first filler (6a), wherein the particles of at least one of the fillers have a higher hardness than the elastomeric material of the sealing body (3).

2. The sealing device according to claim 1, wherein The first filler (6a) is made of carbon.

3. The sealing device according to claim 1 or 2, characterized in that The second filler (6b) is made of PTFE fine powder and / or glass powder and / or phenolic resin.

4. The sealing device according to any one of claims 1 to 3, characterized in that The elastomeric material is additionally provided with particles of a third filler.

5. The sealing device according to any one of the preceding claims, characterized in that, The elastomeric material is made of vulcanized rubber, in particular nitrile rubber (NBR), acrylate rubber (ACM) or fluororubber (FKM).

6. The sealing device according to any one of the preceding claims, characterized in that, The particles of the first filler (6a) and the particles of the second filler (6b) have different geometries.

7. The sealing device according to claim 6, characterized in that, The particles of the first filler (6a) are designed to be spherical or ellipsoidal and the particles of the second filler (6b) are designed to be fibrous, or the particles of the first filler (6a) are designed to be fibrous and the particles of the second filler (6b) are designed to be spherical or ellipsoidal.

8. The sealing device according to any one of the preceding claims, characterized in that, The elastomeric material is provided with 1.5% to 15%, in particular 3% to 7%, of the first filler (6b).

9. The sealing device according to any one of the preceding claims, characterized in that, The elastomeric material is provided with 1.5% to 15%, in particular 1% to 4%, of the second filler (6b).

10. A bearing (10) comprising at least one outer ring (11) and at least one inner ring (12), with at least one sealing device according to any one of the preceding claims spatially arranged between the respective inner ring (11) and the respective outer ring (12), provided with a running plate (4) against which the sealing lip (5) makes sealing contact, and a carrier plate (2) arranged to be rotatable relative to the running plate (4), or the running plate arranged to be rotatable relative to the carrier plate.

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