Sealing Device

Abstract

The present invention relates to a sealing device comprising a sealing element having a carrier plate and a sealing body of elastomeric material molded onto the carrier plate, the sealing body having at least a first sealing lip, the elastomeric material of the sealing body having fillers arranged at least in its region, the elastomeric material having at least the first filler and a second filler different from the first filler, and at least particles of 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 comprising a sealing element having a carrier plate on which a sealing body of elastomeric material is molded, the elastomeric material having, at least in areas, a filler disposed therein, which can be used in a wide variety of applications, such as wheel bearings, bearings for wind turbines, e-mobility applications, agricultural machinery, processing machinery, etc., or in any application in which a dynamic seal comprising such a sealing device is used. [Background technology]

[0002] German Patent Application Publication No. 102018132388 discloses a seal having an elastomer body. The elastomer body at least partially contains a special filler mixture. The elastomer body is, for example, a vulcanized elastomer mixture or a thermoplastic elastomer containing a filler as a filler mixture. One example is the use of PTFE as a friction-reducing substance, which is used as a filler in the seal. However, this has the disadvantage that the seal experiences high levels of wear due to its extremely soft surface and self-lubricating properties. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to propose a sealing element and a bearing device with improved friction properties, in particular lower friction losses in the seal lip contact, which also positively influences the wear of the seal. 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. [Means for solving the problem]

[0004] A sealing device according to the present invention comprises a sealing element having a carrier and a sealing body of elastomeric material molded on the carrier, the sealing body having at least a first sealing lip, the elastomeric material of the sealing body having a filler disposed therein, at least in a region, the elastomeric material having at least a first filler and a second filler different from the first filler, and at least one particle of the filler has a higher hardness than the elastomeric material of the sealing body.

[0005] The carrier may be, for example, a carrier plate made from a metal material, or alternatively, the carrier may be made from a plastic or a fiber composite, etc.

[0006] By adding a combination of at least two different fillers, both friction on the seal and wear on the seal can be reduced. The harder the filler, the more durable the seal. Suitable fillers for the first or second filler can be glass, carbon, graphite, basalt, phenolic resin, or PTFE. The addition of other friction-reducing fillers, such as molybdenum disulfide, aramid, or bronze, is also contemplated.

[0007] The elastomeric material of the sealing body, in particular at least the first sealing lip, is enriched with a filler consisting of a plurality of particles, fibers or powders at least in a region or section by means of a suitable manufacturing method, preferably the entire seal contains the filler.

[0008] Basically, any basic elastomer material is suitable for the sealing body. In particular, nitrile rubbers such as NBR (nitrile butadiene rubber) are suitable. Also conceivable are HNBR (hydrogenated nitrile butadiene rubber), FKM (fluorocarbon rubber), ACM (polyacrylate copolymer), EPDM (ethylene propylene diene (monomer) rubber), etc. Thermoplastic elastomers such as TPE, TPU, TPA, etc., or blends of the above materials can also be used.

[0009] During the mixing process of the elastomer material, also known as the matrix compound, the filler can be added to the mixture in a simple manner, eliminating the need for additional manufacturing or processing steps for one or more components of the sealing element. The elastomer mixture can also be used in sealing devices that include surface-modified counter-running surfaces, which can be expected to further reduce friction. In principle, the filler can be made of a material with a higher hardness than the elastomer material, also known as the matrix compound. However, it is also possible to mix a hard filler with a softer friction-reducing filler.

[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 possible to use barium sulfate as a filler. The addition of relatively hard fillers, such as carbon fiber or phenolic resin, can increase the seal's wear resistance and positively influence the surface microstructure. Friction is reduced by the presence of the filler directly at the friction contact point, which reduces seal friction due to its higher hardness and lower friction compared to rubber.

[0011] Preferably, the second filler is made of PTFE fine powder, glass powder, and / or phenolic resin, or a combination thereof. It is also conceivable to use barium sulfate, particularly in the size range of 30 to 500 μm, as the second filler. Adding these fillers to the elastomer material can further reduce the friction of the seal.

[0012] Advantageously, the particles of the filler deformation body, i.e., the first or second filler, are softer than the material of the counter-running surface. Fillers with such particles are made, in particular, of carbon or plastic, such as PTFE, carbon fiber, thermoplastics or resins. This has the advantage that if the fillers are released from the elastomer material, for example due to wear, they will not damage the components or bearing units to be sealed.

[0013] In a preferred exemplary embodiment, the elastomeric material of the seal comprises particles of a third filler. The third friction-reducing filler is preferably formed from glass powder and / or phenolic resin. Preferably, the elastomeric material is made of vulcanized rubber. Examples of vulcanized rubber that can be used include nitrile rubber (NBR), acrylate rubber (ACM), and fluoro rubber (FKM). The combination of NBR as the elastomeric material with carbon fiber as the first filler, and the combination of PTFE fine powder as the second filler with glass powder as the third filler are particularly preferred in this context.

[0014] Preferably, the particles of the first filler and the particles of the second filler have different geometric shapes. Preferably, the particles of the first filler are spherical or elliptical, the particles of the second filler are fibrous, or vice versa, and the particles of the third filler are powdery. However, the same fillers can be mixed with different geometric shapes. It is also possible that the first filler, the second filler, and the third filler have the same geometric shape. This can occur, for example, when glass powder or carbon fiber powder is used as a filler.

[0015] In principle, filler particles can have any shape or structure. It has been found that ellipsoidal, spherical, and / or fibrous filler particle shapes are advantageous. In other words, the filler can be ellipsoidal, spherical, and / or fibrous particles. One advantage of spherical or ellipsoidal filler particles is that they can be distributed very uniformly throughout the elastomeric material. Furthermore, fibrous filler particles can mechanically reinforce the elastomeric material. The combination of an FKM as an elastomeric material with spherical or fibrous fillers has particularly good friction properties. Irregular particles, i.e., particles with irregular shapes, have the advantage that they can better connect with the polymer matrix than round particles, thus providing better adhesion within the matrix. Fibrous fillers are preferred for improving embeddability in elastomers. Furthermore, fillers can be subjected to special surface treatments, such as sizing, surface activation, or functional groups. Thus, particles can be configured to be regularly and irregularly spherical, ellipsoid, etc.

[0016] During the seal body's manufacturing process, at least some of the spherical, elliptical, and / or fibrous filler particles can accumulate on the surface of the seal body, particularly on the surface of at least the first seal lip. These particles can protrude from the surface and simultaneously be embedded in the elastomer material, or they can be covered by a thin elastomer layer. In the latter case, the elastomer expands over the filler particles placed on the surface as the elastomer crosslinks and then contracts during manufacturing. In either case, the filler particles form the surface of at least the first seal lip. This significantly reduces friction losses on the seal body surface and in the contact area between the seal body and the running plate, without impairing the sealing effect. As the seal wears, the particles become exposed, reducing friction due to their increased hardness and possibly further friction-reducing or self-lubricating properties.

[0017] For spherical or ellipsoidal particles, phenolic resin beads, glass beads, hollow glass beads, PE or HDPE beads with diameters in the range of 5 μm to 200 μm are particularly suitable. Preferably, the spherical and / or ellipsoidal filler particles have a diameter of 10 μm to 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, PEEK, phenolic resin, and beads made of epoxy resin have relatively high durability.

[0018] Fillers consisting of spherical or ellipsoidal particles tend to provide a more uniform structure on the sealing body surface. For a more solid geometry of the sealing body or sealing element, particles with larger diameters can also be used. Elliptical particles are also preferably characterized by a diameter-to-length ratio between 1:1 and 1:10, preferably between 1:1.1 and 1:1:5.

[0019] The preferred filler fibrous particles have a diameter of 4 to 30 μm, and the length of the fibers remaining in the compound after mixing is 50 to 1,000 μm. Glass, carbon, and PTFE are particularly suitable due to their relatively high resistance to lubricants and their chemical inertness. A combination of a hard filler and a self-lubricating filler, such as PTFE, is particularly suitable because it reduces friction after a thin elastomer layer stretched over the filler particles placed on the surface of the seal body wears, even when the friction or contact area between the seal lip and the running plate increases as a result of wear.

[0020] Particularly preferably, the elastomeric material of the seal comprises 1.5% to 15%, in particular 3% to 7%, of a first filler, which is preferably carbon or carbon fibre.

[0021] In another embodiment, the elastomer material comprises 1.5% to 15%, particularly 1% to 4%, of a second filler. The second filler is preferably PTFE fine powder. This combination of the first and second fillers in the seal allows for a durable seal with optimized friction.

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

[0023] The present invention also relates to a bearing including at least one outer ring and at least one inner ring, at least one sealing device spatially disposed between each inner ring and each outer ring, the sealing device including a sealing element, the sealing element including a carrier, an elastomeric material sealing body molded on the carrier, the sealing body including at least a first sealing lip, the elastomeric material of the sealing body including fillers disposed therein at least in a region thereof, the elastomeric material including at least the first filler and a second filler, at least one particle of the filler having a higher hardness than the elastomeric material of the sealing body, a running plate with which the sealing lip makes sealing contact, and the carrier is rotatably disposed relative to the running plate, or vice versa. This sealing device can be used in automobiles, trucks, and any application in which a seal is used under dynamic conditions, i.e., not exclusively for sealing bearings.

[0024] Preferably the bearing is a vehicle wheel bearing.

[0025] Further means for improving the present invention will be explained in more detail below with reference to the drawings, together with a description of two preferred exemplary embodiments of the present invention, in which identical or similar elements are provided with the same reference signs. [Brief explanation of the drawings]

[0026] [Figure 1] 1 shows a simplified schematic cross-sectional view of a wheel bearing having two sealing devices according to the invention; [Figure 2] 1 shows a schematic cross-sectional view of a first sealing device according to a first exemplary embodiment; [Figure 3] 2 shows a schematic cross-sectional view of a second sealing device of a wheel bearing according to a first embodiment. [Figure 4] 2 shows a schematic cross-sectional view of a first sealing device according to a second embodiment; [Figure 5] 4 shows a schematic cross-sectional view of a second sealing device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] FIG. 1 shows an example of a bearing 10 for a vehicle (not shown), 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 a wheel hub 22. Hereinafter, the first inner ring 12 is referred to as the flange of the wheel hub 22, which forms the raceways along which the first row of rolling elements 23 of the bearing 10 rotate. Meanwhile, the second inner ring 25 is pressed against the wheel hub 22 for structural reasons. In this case, two rows of rolling elements 23, 27 are spatially arranged between the outer ring 11 and the inner ring 12, 25. Furthermore, the interior 8 of the bearing 10 is sealed from the outer region 9 by two sealing elements 1, 24. The detailed structure of the sealing elements 1, 24 is shown in more detail for a first exemplary embodiment in FIGS. 2 and 3 and for a second exemplary embodiment in FIGS. 4 and 5. The sealing elements 1, 24 of the different embodiments differ only in the configuration of the sealing body 3. Each seal element 1, 24 has a carrier 2 and a running plate 4, and the carrier 2 of each seal element 1, 24 is non-rotatably arranged on the outer ring 11, and the running plate 4 of each seal element 1, 24 is non-rotatably arranged on the first inner ring 12 or the second inner ring 25. The carrier 2 is rotatably arranged relative to the running plate 4.

[0028] In this case, the carrier 2 has an L-shaped cross-section and comprises a substantially axial portion 16 and a substantially radial portion 17. The carrier 2 is press-fitted onto the outer ring 11 by the axial portion 16. The running plates 4 are C-shaped in cross-section, and each running plate 4 is press-fitted onto the first inner ring 12 or pressed onto the second inner ring 25 by a first substantially axial leg 20. As shown in Figures 3 and 5, the running plates 4 can have a vulcanized cord ring (not described in detail here) which interacts with a sensor device (not shown here), for example, to determine the rotational speed.

[0029] The seal body 3 is vulcanized onto the carrier 2 of the respective seal element 1, 24 and has elastically deformable first, second, and third seal lips 5, 18, 26, respectively, extending at an angle from the seal body 3 toward the running plate 4. The first and second seal lips 5, 18 are in sealing contact with a first counter-running surface 7 on the radial leg 19 of the running plate 4. For the first seal element 1 shown in FIGS. 2 and 4, the third seal lip 26 is in sealing contact with a second counter-running surface 21 on the second substantially axial leg 28 of the running plate 4. For the second seal element 24 shown in FIGS. 3 and 5, the third seal lip 26 is in sealing contact with a second counter-running surface 21 on the first substantially axial leg 20 of the running plate 4.

[0030] The sealing body 3 is a sealing ring made of an elastomeric material, such as NBR, in which fillers 6a, 6b are disposed. In this regard, the elastomeric material is formed of a combination of at least two different fillers 6a, 6b.

[0031] The first filler 6a has substantially spherical particles 13 in the first exemplary embodiment shown in FIGS. 1 to 3 and substantially fibrous particles 14 in the second exemplary embodiment shown in FIGS. 4 and 5. The fillers 6a, 6b are uniformly distributed throughout the elastomeric material of the seal body 3, with some of the particles 13, 14 located on the surface of the seal body 3, particularly on the seal lips 5, 18, 26 that contact the running plate 4. The fillers 6a, 6b have a higher hardness than the elastomeric material of the seal body 3, and their placement on the surface 15 has the effect of structuring the surface 15 of the seal body 3. Due to the geometric shape of the particles 13, 14 of the fillers 6a, 6b and the inherent material properties, the structuring of the surface 15 reduces friction at the seal lip contact with the running plate 4, which in turn reduces torque in the bearing 10.

[0032] 2 and 3, the particles 13 of the first fillers 6a and 6b are configured to be spherical. The spherical particles 13 can be made of plastic, elastomer, glass, carbon, or ceramic. The particles 13 can also be entirely or partially ellipsoidal. The first filler 6a is preferably mixed into the sealing body 3 at a higher rate than the second filler 6b. The first filler 6a is particularly preferably made of carbon fiber. It is preferably mixed into the elastomer material of the sealing body 3 at a rate of 1.5% to 15%, particularly preferably 3% to 7%. The second filler 6b is different from the first filler and can have a different geometric shape.

[0033] 2 and 3, the second filler 6b is configured to be fibrous. The second filler 6b is preferably composed of PTFE fine powder, glass powder, or phenolic resin beads. The second filler 6b is preferably mixed in an amount of 1.5% to 15%, and more preferably 1% to 4%, relative to the elastomer material of the seal body 3. Therefore, by adding a combination of two different fillers 6a and 6b to the seal body 3, friction and wear of the seal can be reduced.

[0034] 4 and 5, the particles 14 of the first filler 6a are configured to be fibrous. The fibrous particles 14 can be made of carbon fiber, plastic, elastomer, glass, ceramic, or a mixture thereof. Carbon fiber is chemically inert, which can improve the chemical compatibility of the respective sealing elements 1, 24. In this embodiment, the particles of the second filler 6b are formed to be spherical. In this exemplary embodiment, the sealing body 3 is made of 1.5% to 15% of the first filler 6a, particularly carbon fiber, and 1.5% to 15% of the second filler 6b, preferably an elastomer material such as NBR mixed with PTFE fine powder, glass powder, or phenolic resin beads.

[0035] It is also conceivable to provide a first, second and third filler in the elastomeric material of the sealing body 3. It is particularly preferred that the third filler is made from PTFE fine powder, glass powder or phenolic resin beads. [Explanation of symbols]

[0036] 1 first sealing element 2. Career 3 Seal body 4 running plates 5 First sealing lip 6a First Filler 6b Second Filler 7 First opposing running surface 8 inside 9 Outer area 10 Bearings 11 Outer ring 12 The First Inner Circle 13 Spherical particles 14 Fibrous particles 15 Surface 16 Axial cross section of carrier plate 17 Radial cross section of carrier plate 18 Second sealing lip 19 Running plate axial leg 20 first axial leg of running plate 21 Second opposing running surface 22 Wheel hub 23 First row rotation elements 24 Second sealing element 25 The Second Inner Circle 26 Third sealing lip 27 Second row rotation elements 28 Second axial leg of running plate

Claims

1. 1. A sealing device comprising a sealing element (1, 24), the sealing element (1, 24) having a carrier (2), a sealing body (3) of elastomeric material molded on the carrier (2), the sealing body (3) having at least a first sealing lip (5), the elastomeric material of the sealing body (3) having, at least in regions, fillers (6 a, 6 b) arranged therein, the elastomeric material having at least a first filler (6 a) and a second filler (6 b) different from the first filler (6 a), and at least one particle of the filler has a higher hardness than the elastomeric material of the sealing body (3).

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

3. 3. The sealing device according to claim 1 or 2, characterized in that the second filler (6b) is made from 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 further comprises particles of a third filler.

5. 5. The sealing device according to claim 1, wherein the elastomeric material is made from vulcanized rubber, in particular nitrile rubber (NBR), acrylate rubber (ACM) or fluororubber (FKM).

6. The sealing device according to any one of claims 1 to 5, characterized in that the particles of the first filler (6a) and the particles of the second filler (6b) have different geometric shapes.

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

8. Sealing device according to any one of claims 1 to 7, characterized in that the elastomeric material comprises 1.5% to 15%, in particular 3% to 7% of the first filler (6b).

9. Sealing device according to any one of the preceding claims, characterized in that the elastomeric material comprises 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), wherein at least one sealing device according to any one of claims 1 to 9 is spatially arranged between each of the inner rings (11) and each of the outer rings (12), and wherein a running plate (4) is provided with which the sealing lip (5) is in sealing contact, and wherein the carrier plate (2) is arranged rotatably relative to the running plate (4), or vice versa.

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