Sealing device and bearing unit having a sealing device

Abstract

A sealing device (1) is disclosed, the sealing device (1) comprising at least one seal holder (6), where the at least one seal holder (6) comprises an annular sealing surface (14) configured to form a non-contact seal with a mating surface, where the sealing surface (14) is arranged opposite the mating surface (16), where the sealing surface (14) is configured to form a non-contact seal with the mating surface (16). The sealing surface (14) and the mating surface (16) are arranged such that a gap (18) is formed between the sealing surface (14) and the mating surface (16), the sealing surface (14) and / or the mating surface (16) being at least partially provided with at least one oleophobic coating (20).

Description

Technical Field

[0001] The present invention relates to a sealing device, in particular to a non-contact sealing device. In addition, the present invention relates to a bearing unit having a sealing device. Background Art

[0002] Non-contact seals or sealing devices are often used in applications where it is desirable to reduce friction torque and / or obtain maximum speed limitation, such as in rolling bearings. However, non-contact seals may have a higher risk of suffering from lubricant leakage.

[0003] It is therefore an object of the present invention to increase the resistance of a sealing device to lubricant leakage. Summary of the invention

[0004] This object is solved by a sealing device according to technical solution 1.

[0005] In the following, a sealing device is provided. The sealing device is a non-contact sealing device and includes at least one seal holder, the at least one seal holder includes an annular sealing surface, the annular sealing surface is configured to form a non-contact seal together with a counter face, wherein the sealing surface is opposite to the counter face so that a gap is formed between the sealing surface and the counter face. The sealing device may include a single sealing surface or more than one sealing surface. For example, the sealing holder may include a first annular sealing surface and a second annular sealing surface, and the first annular sealing surface and the second annular sealing surface may be configured concentrically. The counter face may be a part of an element to be sealed (such as a bearing component, a bearing ring) and / or an element attached to an element to be sealed (such as a sleeve, a nut, a rotating shaft, a seat (housing), etc.), or a part of a sealing device (for example, if the sealing device is configured as a cassette gasket). The size of the gap may be between 0.1 mm and 5 mm, preferably between 0.23 mm and 2 mm.

[0006] In order to enhance the resistance of the sealing device to lubricant leakage, the sealing surface and / or the mating surface is at least partially provided with at least one oleophobic coating layer. In addition, the thickness of the oleophobic coating layer may be between 1 μm and 100 μm, preferably between 5 μm and 25 μm. In addition, multiple oleophobic coating layers may be provided.

[0007] Preferably, the oleophobic coating can be made of a material with low surface energy, wherein the surface energy is less than 0.030 N / m, preferably less than 0.020 N / m. For example, the oleophobic coating may include PFA, Teflon, silicone, but is not limited to these materials. In addition, the oleophobic coating may be applied by a sol-gel dipping process, spraying, plasma deposition process, or any other suitable process. In addition, a curing process may be used, wherein the curing temperature is preferably between 50°C and 350°C, depending on the composition of the coating.

[0008] Preferably, the sealing surface and / or the mating surface is at least partially provided with at least one second oleophobic coating. In addition, a plurality of second oleophobic coatings may be provided. The second oleophobic coating may be made of a material having a low surface energy, wherein the surface energy is less than 0.030 N / m, preferably less than 0.020 N / m. For example, the second oleophobic coating may include PFA, Teflon, silicone, but is not limited to these materials. The second oleophobic coating may further enhance the resistance of the sealing device to lubricant leakage. The material of the oleophobic coating and the material of the second oleophobic coating may be the same or different from each other. In addition, if the materials of the oleophobic coating and the second oleophobic coating are different, the oleophobic coating and the second oleophobic coating may be configured alternately. As another option, the oleophobic coating and the second oleophobic coating may be grouped.

[0009] Preferably, at least one oleophobic coating and / or at least one second oleophobic coating may be provided on both the sealing surface and the counter surface. This may further increase the resistance to leakage.

[0010] Moreover, the second oleophobic coating is spaced apart from the oleophobic coating in the radial direction of the annular sealing surface. In addition, if multiple oleophobic coatings and / or second oleophobic coatings are provided, the coatings may be spaced apart from each other in the radial direction of the annular sealing surface. Alternatively, if the oleophobic coating and the second oleophobic coating are made of different materials, the oleophobic coating and the second oleophobic coating may contact or even overlap.

[0011] In addition, the oleophobic coating and / or the at least one second oleophobic coating may have at least one gap in the circumferential direction. For example, the oleophobic coating and / or the at least one second oleophobic coating may be discontinuous in the circumferential direction. The at least one gap in the oleophobic coating and / or the at least one second oleophobic coating may allow the lubricant accumulated between the two oleophobic layers to be guided back to its origin, such as the interior of the bearing.

[0012] Preferably, at least one gap in the oleophobic coating and at least one gap in the second oleophobic coating are arranged alternately with each other. This allows the leakage resistance of the sealing device to be still enhanced while allowing the lubricant trapped between the two oleophobic coatings to be guided back. If the sealing device has multiple oleophobic coatings and / or second oleophobic coatings, at least one of the coatings may be continuous in the circumferential direction, while the other coatings may have at least one gap in the circumferential direction. This allows the leakage resistance of the sealing device to be further enhanced.

[0013] As another option, the oleophobic coating and / or the at least one second oleophobic coating may be continuous in the circumferential direction. This has the advantage that the resistance of the sealing device to lubricant leakage may be further enhanced.

[0014] According to another embodiment, the oleophobic coating and / or at least one second oleophobic coating forms a pattern in the radial direction of the annular sealing surface. For example, the pattern may be a periodic pattern, such as a sine wave pattern, a sawtooth wave pattern, a square wave pattern, etc. This has the advantage that a guide structure for the lubricant may be formed by at least one of the oleophobic coating and / or at least one second oleophobic coating. The pattern may be formed by a discontinuous and / or continuous oleophobic coating.

[0015] Preferably, the oleophobic coating and / or at least one second oleophobic coating may have a width in the radial direction of the annular sealing surface. In addition, the width of at least one oleophobic coating may be greater than 0.5 times the size of the gap between the sealing surface and the mating surface. For example, the width may be between 0.1 mm and 5 mm. In addition, the widths of the oleophobic coating and / or the second oleophobic coating may be equal to or different from each other. For example, the distance between the two oleophobic coatings may be 1.5 to 5 times the width of the oleophobic coating.

[0016] According to another embodiment, each of the sealing surface and the mating surface has at least one oleophobic coating and / or at least one second oleophobic coating. Preferably, the oleophobic coating and / or the second oleophobic coating of the sealing surface and the oleophobic coating and / or the second oleophobic coating of the mating surface can be configured at the same radial position or different radial positions in the radial direction of the sealing surface. In other words, at least one oleophobic coating of the sealing surface and at least one oleophobic coating of the mating surface are configured on top of each other or offset from each other so that they alternate in the radial direction of the sealing surface.

[0017] Furthermore, the sealing surface and / or the counter surface can be completely coated with an oleophobic coating. This has the advantage that the resistance of the sealing device to lubricant leakage is further increased.

[0018] Preferably, at least one oleophobic coating and / or at least one second oleophobic coating is configured in a groove on the sealing surface and / or the mating surface and / or is configured as a raised pattern ( / elevated pattern) on the sealing surface and / or the mating surface. The depth of the groove can be between 2μm and 500μm, preferably between 5μm and 50μm, and the groove width can be between 0.1mm and 5mm, preferably greater than 0.5 times the gap between the non-contact seal and the mating surface. By configuring the oleophobic coating and / or at least one second oleophobic coating in the groove, the risk of coating wear during bearing operation ( / work) can be further reduced, and the oleophobic coating inside the groove can remain intact ( / intact) during operation ( / work) (operation). Alternatively or additionally, at least one oleophobic coating and / or at least one second oleophobic coating is configured as a raised pattern on the sealing surface and / or the mating surface.

[0019] Furthermore, it is also possible to provide a sealing surface and / or a counterface with a groove and to coat the entire sealing surface and / or the counterface. The groove can reduce the risk of coating wear during operation, because even if the coating on the remaining surface is worn away, the oleophobic coating inside the groove will remain intact during bearing operation, and even if part of the coating on the sealing surface and / or the counterface has been worn away, the coating inside the groove will provide the function of preventing lubricant leakage and contamination.

[0020] According to another aspect, a bearing unit is provided, comprising at least one rotating element and at least one stationary element, wherein the bearing unit further comprises at least one sealing device as described above, wherein the sealing device is attached to one of the at least one rotating element and the at least one stationary element, and the mating surface is formed on the other of the at least one rotating element and the at least one stationary element.

[0021] Further preferred embodiments are defined in the dependent claims as well as in the description and drawings. Hence, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, preferred embodiments of the present invention are described with respect to the accompanying drawings, wherein the drawings are merely exemplary and are not intended to limit the scope of protection. The scope of protection is defined solely by the appended claims.

[0023] The accompanying drawings show:

[0024] Figure 1 : A schematic diagram of a sealing device according to a first embodiment,

[0025] Figure 2 : A schematic diagram of a sealing device according to a second embodiment,

[0026] Figure 3 : A schematic diagram of a sealing device according to a third embodiment, and

[0027] Figure 4 : Schematic diagram of a sealing device according to a fourth embodiment.

[0028] Reference numerals list

[0029] 1 Sealing device

[0030] 2 Rotating components

[0031] 4. Fixing components

[0032] 6 Seal retainer

[0033] 8 Attachment

[0034] 10. Shielding

[0035] 12 Sealing part

[0036] 14 Sealing surface

[0037] 16 Mating surface

[0038] 18 Gap

[0039] 20 Oleophobic coating

[0040] 22 slots DETAILED DESCRIPTION

[0041] In the following, identical or functionally similar elements are denoted by the same reference numerals.

[0042] Figure 1 A sealing device 1 according to a first embodiment is shown. Figure 1 In the embodiment, the sealing device 1 is arranged on the axial outer side of the rolling bearing having the rotating component 2 and the stationary component 4. Figure 1 In the embodiment, the rotating component 2 is an inner ring. However, as another option, the rotating component may be a shaft, a sleeve, a nut that fixes the inner ring and / or sleeve to the shaft, etc. In addition, Figure 1The fixed component 4 in the embodiment is an outer ring. However, as another option, the fixed component 4 can be a seat ( / shell) (housing), a stub shaft (stub shaft), a sleeve, a nut fixing the outer ring and / or the sleeve, etc.

[0043] The sealing device 1 is attached to the rotating component 2 and includes a sealing retainer 6, which includes an attachment portion 8, which extends in the axial direction of the bearing and is constructed to be attached to the rotating component 2, for example, by press-fitting. In addition, the sealing retainer includes a shield portion 10 extending in the radial direction and a sealing portion 12 extending in the axial direction, the shield portion 10 extending in the radial direction is connected to the attachment portion 8, and the sealing portion 12 extending in the axial direction is substantially parallel to the attachment portion 8 and connected to the shield portion 10. The sealing retainer 6 can be made of metal, for example, made of steel. The attachment portion 8, the shield portion 10 and the sealing portion 12 can be formed integrally. As another option, the attachment portion 8, the shield portion 10 and the sealing portion 12 can be connected to each other by any suitable method (for example, welding, adhesive bonding, by screws, etc.).

[0044] The sealing portion 12 of the sealing retainer has an annular sealing surface 14, which is configured to be opposite to a counter face 16 and is constructed to form a non-contact seal together with the counter face 16, wherein a gap 18 is formed between the sealing surface 14 and the counter face 16. Figure 1 The mating surface 16 is formed on the fixed component 4. The size of the gap 18 can be between 0.1 mm and 5 mm, preferably between 0.23 mm and 2 mm.

[0045] In order to improve the resistance of the sealing device 1 to lubricant leakage, the sealing surface 14 is provided with four oleophobic coating layers 20, each of which is arranged in a groove 22. The depth of the groove can be between 2 μm and 500 μm, preferably between 5 μm and 50 μm, and the groove width can be between 0.1 mm and 5 mm, preferably greater than 0.5 times the gap 18 between the sealing surface 14 and the mating surface 16.

[0046] The thickness of each coating 20 in the radial direction may be between 1 μm and 100 μm, preferably between 5 μm and 25 μm. Therefore, the thickness of the coating 20 is preferably less than the depth of the groove 22. The oleophobic coating 20 is made of a material having a low surface energy, wherein the surface energy is less than 0.030 N / m, preferably less than 0.020 N / m. For example, the oleophobic coating 20 may include PFA, Teflon, silicone, but is not limited to these materials. In addition, the oleophobic coating may be applied by a sol-gel dip process, spraying, a plasma deposition process, or any other suitable process. In addition, a curing process may be used, wherein the curing temperature is preferably between 50°C and 350°C, depending on the composition of the coating. It is also possible that in the case of more than one oleophobic coating 20, such as Figure 1 As shown, a subset of these oleophobic coatings 20 are made of a different low surface energy material than the rest of the oleophobic coatings 20 .

[0047] As from Figure 1 It can be seen that the oleophobic coatings 20 are spaced apart from each other in the radial direction of the annular sealing surface 14 (i.e., the axial direction of the bearing). For example, the distance between two oleophobic coatings 20 may be between 1.5 and 5 times the width of the oleophobic coating 20. Each oleophobic coating 20 has a width in the radial direction of the annular sealing surface (i.e., the axial direction of the bearing), wherein the width of the coating 20 may be greater than 0.5 times the size of the gap 18 between the sealing surface 14 and the mating surface 16. Preferably, the width may be between 0.1 mm and 5 mm. Moreover, the widths of the oleophobic coatings 20 may be equal to or different from each other.

[0048] At least one oleophobic coating 20 may have at least one gap in the circumferential direction. In other words, at least one oleophobic coating 20 may be discontinuous in the circumferential direction. Preferably, if two oleophobic coatings 20 have at least one gap, the gaps may be arranged alternately with each other. This still allows the leakage resistance of the sealing device to be enhanced while allowing the lubricant trapped between the two oleophobic coatings 20 to be guided back into the bearing interior. Alternatively or additionally, at least one oleophobic coating 20 may be continuous in the circumferential direction.

[0049] Figure 2 A sealing device 1 according to a second embodiment is shown, wherein: Figure 2 The sealing device and Figure 1 The sealing device of is different in that both the sealing surface 14 and the mating surface 16 are provided with at least one oleophobic coating. Figure 2 As can be seen, the oleophobic coating 20 on the mating surface 16 covers the entire mating surface 16, while the sealing surface 14 is provided with three oleophobic coatings 20 separated from each other. Figure 1 In contrast, the coating 20 is disposed on top of each surface and not in the grooves 22 .

[0050] Figure 3 A sealing device 1 according to a third embodiment is shown, wherein: Figure 3 The sealing device and Figure 1 The difference of the sealing device of is that both the sealing surface 14 and the mating surface 16 are provided with a plurality of oleophobic coatings 20, which are all provided on top of each surface and not in the grooves 22. Figure 3 It can be seen that the oleophobic coating 20 of the sealing surface 14 and the oleophobic coating of the counter surface 16 are arranged offset from one another, such that they alternate in the radial direction of the sealing surface 14 .

[0051] Figure 4 A sealing device 1 according to a fourth embodiment is shown, wherein: Figure 4 The sealing device and Figure 1 The sealing device of is different in that both the sealing surface 14 and the counter surface 16 are provided with a number of oleophobic coatings 20, each oleophobic coating 20 being arranged in a groove 22. In addition, both the sealing surface 14 and the counter surface 16 are completely coated with an additional oleophobic coating 20.

[0052] In summary, lubricant leakage of the non-contact seal can be prevented or at least reduced by providing a coating 20 with low surface tension, i.e., an oleophobic coating, on at least one of the sealing surface 14 and the counter surface 14. By configuring at least one oleophobic coating 20 in the groove, the risk of coating wear during bearing operation is further reduced, and the oleophobic coating inside the groove can remain intact during operation.

Claims

1. A sealing device (1), comprising at least one sealing retaining member (6), wherein: The at least one sealing retainer (6) comprises an annular sealing surface (14), the annular sealing surface (14) being configured to form a non-contact seal together with a mating surface, wherein the sealing surface (14) is arranged opposite to the mating surface (16) so that a gap (18) is formed between the sealing surface (14) and the mating surface (16), characterized in that: The sealing surface (14) and / or the counter surface (16) are at least partially provided with at least one oleophobic coating (20).

2. The sealing device (1) according to claim 1, characterized in that The sealing surface (14) and / or the counter surface (16) are at least partially provided with at least one second oleophobic coating (20).

3. The sealing device (1) according to claim 2, characterized in that The at least one second oleophobic coating (20) is spaced apart from the oleophobic coating (20) in a radial direction of the annular sealing surface (14).

4. The sealing device (1) according to any one of the preceding claims, characterized in that The oleophobic coating (20) and / or the at least one second oleophobic coating (20) has at least one gap in the circumferential direction of the annular sealing surface (14).

5. The sealing device (1) according to any one of claims 2 to 4, characterized in that The at least one gap in the oleophobic coating (20) and the at least one gap in the at least one second oleophobic coating (20) are arranged alternately with each other.

6. The sealing device (1) according to any one of claims 1 to 3, characterized in that The oleophobic coating (20) and / or the at least one second oleophobic coating (20) is continuous in the circumferential direction of the annular sealing surface (14).

7. The sealing device (1) according to any one of the preceding claims, characterized in that The oleophobic coating (20) and / or the at least one second oleophobic coating (20) forms a pattern in a radial direction of the annular sealing surface (14).

8. The sealing device (1) according to any one of the preceding claims, characterized in that The oleophobic coating (20) and / or the at least one second oleophobic coating (20) has a width in a radial direction of the annular sealing surface (14).

9. The sealing device (1) according to claim 8, characterized in that The widths of the oleophobic coating (20) and the at least one second oleophobic coating (20) are equal to or different from each other.

10. The sealing device (1) according to any one of the preceding claims, characterized in that The surface (14) and the mating surface (16) have at least one oleophobic coating (20), and wherein the at least one oleophobic coating (20) of the sealing surface (14) and the at least one oleophobic coating (20) of the mating surface (16) are arranged at the same radial position or different radial positions in the radial direction of the sealing surface (14).

11. The sealing device (1) according to any one of the preceding claims, characterized in that The sealing surface (14) and / or the counter surface (16) are completely coated with the oleophobic coating (20).

12. The sealing device (1) according to any one of the preceding claims, characterized in that The oleophobic coating (20) and / or the at least one second oleophobic coating (20) are arranged in a groove (22) on the sealing surface (14) and / or the mating surface (16) and / or are arranged as a raised pattern on the sealing surface (14) and / or the mating surface (16).

13. A bearing unit comprising at least one rotating element (2) and at least one fixed element (4), wherein: The bearing unit further comprises at least one sealing device (1) according to any one of the preceding claims, wherein the sealing device is attached to one of the at least one rotating element (2) and the at least one fixed element (4), and the mating surface (16) is formed on the other of the at least one rotating element (2) and the at least one fixed element (4).

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