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DE-102024133211-A1 - Sealing unit with a synthetic resin silicone coating

DE102024133211A1DE 102024133211 A1DE102024133211 A1DE 102024133211A1DE-102024133211-A1

Abstract

The invention relates to a sealing unit (1) comprising a sealing carrier (2), a sealing lip unit (3) having at least one sealing lip (3.1) and held by the sealing carrier (2), and a sealing washer (4) that is in contact with the at least one sealing lip (3.1). The at least one sealing lip (3.1) is coated with a synthetic resin silicone (5.1). The present invention further relates to a wheel bearing unit (RL) comprising such a sealing unit (1).

Inventors

  • Marco Krapf

Assignees

  • Schaeffler Technologies AG & Co. KG

Dates

Publication Date
20260513
Application Date
20241113

Claims (10)

  1. Sealing unit (1) with a sealing carrier (2), a sealing lip unit (3) which has at least one sealing lip (3.1) and is held by the sealing carrier (2), and with a sealing disc (4) which is in contact with the at least one sealing lip (3.1), characterized in that the at least one sealing lip (3.1) is coated with a synthetic resin silicone (5.1).
  2. Sealing unit (1) according Claim 1 , wherein the entire sealing unit (1) is coated with the synthetic resin silicone (5.1, 5.2).
  3. Sealing unit (1) according Claim 1 or 2 , wherein the sealing unit (1) itself has an elastomer surface.
  4. Sealing unit (1) according to one of the Claims 1 until 3 , wherein the synthetic resin silicone (5.1, 5.2) is transparent.
  5. Sealing unit (1) according to one of the Claims 1 until 4 , wherein the thickness of the synthetic resin silicone coating (5.1, 5.2) is between 3 µm and 12 µm.
  6. Sealing unit (1) according to one of the Claims 1 until 5 , wherein the synthetic resin silicone comprises the following components: a binder, which is a synthetic resin and/or a silicone resin, a filler or additive and a solvent.
  7. Sealing unit (1) according to one of the Claims 1 until 6 , wherein the at least one sealing lip (3.1) has a sealing lip axial section (3.1a) extending from the sealing carrier (2) in the axial direction (A), and a sealing lip transverse section (3.1b) directly adjoining the sealing lip axial section (3.1a), which extends obliquely from the sealing lip axial section (3.1a) in the axial direction (A) towards the sealing disc (4), and only the sealing lip transverse section (3.1b) is coated with the synthetic resin silicone (5.1, 5.2).
  8. Sealing unit (1) according Claim 7 , wherein the sealing disc (4) has a sealing disc axial section (4.2) and a sealing disc radial section (4.3) and the at least one sealing lip (3.1) is arranged above the sealing disc axial section (4.2) and only the section of the sealing lip transverse section (3.1b) is coated with the synthetic resin silicone (5.1, 5.2) which faces the sealing disc axial section (4.2).
  9. Sealing unit (1) according Claim 7 , wherein the sealing lip unit (3) has two sealing lips (3.1, 3.2) whose sealing lip cross section (3.1b, 3.2b) is each coated with the synthetic resin silicone (5.1, 5.2).
  10. Wheel bearing unit (RL) comprising an outer ring (6), an inner ring (7), a rolling bearing unit (8) and the sealing unit (1) according to one of the preceding claims, which is arranged between the outer ring (6) and the inner ring (7).

Description

The present disclosure relates to a sealing unit, in particular for sealing a wheel bearing unit, comprising a sealing carrier, a sealing lip unit having at least one sealing lip and being held by the sealing carrier, and a sealing disc which is in contact with the at least one sealing lip. A wheel bearing unit serves to support a vehicle wheel and is typically located between the vehicle's transmission and the wheel. Such a wheel bearing unit is usually designed using a rolling bearing system. It is typically sealed to prevent water from entering the unit. Against this background, for example the printed text reveals DE 10 2017 100 765 A1 A rolling bearing or wheel bearing unit consists of a seal carrier pressed onto an outer ring and a sealing washer (also called a flinger) attached to an inner ring. This combination of seal carrier and sealing washer forms a sealing unit for the wheel bearing unit. However, a disadvantage is that water can penetrate the bearing at the points between the outer ring and the seal carrier, as well as between the sealing washer and the inner ring. This leads to corrosion and significantly reduces the service life of the wheel bearing unit. To address this problem, a further development of a seal or sealing unit for a wheel bearing unit in the prior art provided a sealing lip unit between the seal carrier and the sealing disc. This sealing lip unit has at least one sealing lip that is in contact with these two components. In such a seal, the at least one sealing lip contacts the sealing disc, resulting in frictional forces in practice. These frictional forces within the sealing unit lead to increased wear of at least one sealing lip or the entire sealing unit, thus reducing the safety of such a sealing unit. In the prior art, to reduce friction, the sealing units, or in particular at least one sealing lip, were coated with various materials, mostly PTFE-containing materials. However, the coatings do not adhere to the surface of the sealing unit, which is often made of an elastomer, or they detach and have a stiffening effect on the sealing unit. With the materials used in the prior art, this results in a significantly higher contact force of the sealing lip against the contact surface of the sealing disc, which in turn leads to an increase in friction and frictional forces. Against this background, the present disclosure aims to provide a sealing unit in which the frictional forces that occur can be (significantly) reduced. This problem is solved by the subject matter with the features of the independent claim and by the subject matter with the features of the dependent claim. Advantageous embodiments are the subject of the dependent claims. The sealing unit according to independent claim 1, which is used in particular for sealing a wheel bearing unit, preferably for a vehicle, comprises a sealing carrier, a sealing lip unit having at least one sealing lip and held by the sealing carrier, and a sealing disc that is in contact with the at least one sealing lip. According to the disclosure/invention, the at least one sealing lip is coated with a synthetic silicone resin. In other words, the at least one sealing lip has a synthetic silicone resin coating, in particular a PTFE-free coating. Such an optimized sealing unit, at least one of whose sealing lip is coated with the synthetic resin silicone, can significantly reduce friction or a generated frictional torque, more precisely by 18%, compared to uncoated sealing units. The synthetic resin silicone coating protects the underlying material of at least one sealing lip or the sealing unit (often an elastomer) from abrasion and wear. Accordingly, the sealing unit according to the invention has a higher wear resistance than conventional sealing units. Thus, the service life of the sealing unit according to the invention is also increased compared to conventional sealing units. Advantageously, the silicone resin used is PTFE (polytetrafluoroethylene)-free and contains no components belonging to the PFAS group. PTFE belongs to the PFAS group, which stands for "per- and polyfluoroalkyl substances." Materials containing PFAS are harmful to health and should therefore not be used. In contrast, the PTFE-free silicone resin is safe from a health perspective. Furthermore, synthetic silicone resin is highly thermally resistant. This means that synthetic silicone resins can withstand high temperatures without altering their physical properties. Coating the sealing unit, or at least one sealing lip, with synthetic silicone resin allows for a temperature range of -40°C to 180°C for the sealing unit. Furthermore, the coating of at least one sealing lip or the sealing unit with synthetic resin silicone ensures less adhesion of dirt or dirt deposits to the sealing unit compared to conventional sealing units. This also increases the wear resistance of the sealing unit according to the invention. Furthermore, the synthetic silicone resin used for t