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DE-102024133162-A1 - Seal with friction-reducing etched structure; method for surface treatment of a seal

DE102024133162A1DE 102024133162 A1DE102024133162 A1DE 102024133162A1DE-102024133162-A1

Abstract

The invention relates to a seal (1), for example for a wheel bearing, a gearbox, an e-bike, a wind turbine, an agricultural machine, made of an elastomer (2), such as rubber, for example NBR, with an outer surface (3) for contact with a sealing partner (4), wherein a friction-reducing geometric structure is introduced into the outer surface (3) by means of etching. The invention also relates to a method for surface treatment of an outer surface (3) of a seal (1).

Inventors

  • Marco Krapf

Assignees

  • Schaeffler Technologies AG & Co. KG

Dates

Publication Date
20260513
Application Date
20241113

Claims (10)

  1. Seal (1) made of an elastomer (2) with an outer surface (3) for contact with a sealing partner (4), characterized in that a friction-reducing geometric structure is introduced into the outer surface (3) by means of an etching.
  2. Seal (1) according to Claim 1 characterized by the fact that the structure is formed as a micro-, macro- and/or nanostructure.
  3. Seal (1) after one of the Claims 1 or 2 , characterized in that the etching uses an acid or alkaline solution.
  4. Seal (1) after one of the Claims 1 until 3 characterized by the fact that the structure is formed as a texture.
  5. Seal (1) after one of the Claims 1 until 4 , characterized in that the elastomer (2) is designed as NBR.
  6. Seal (1) after one of the Claims 1 until 5 , characterized in that the elastomer (2) contains fillers which are exposed by etching.
  7. Seal (1) after one of the Claims 1 until 6 , characterized in that the friction-reducing geometric structure is caused by reduction of the contact area (8) and/or by activation of the outer surface (3) of the sealing lips (6, 7).
  8. Method (9) for surface treatment of an outer surface (3) of a seal (1), for example according to one of the Claim 1 until 3 , wherein in an optional first step (10) a surface preparation is carried out to clean and/or pretreat the seal (1), in a second step (11) carried out thereafter an etching is used for an elastomer surface treatment and in an optional third step (12) following the second step a stopping of the chemical reaction started by the etching is achieved.
  9. Procedure according to Claim 8 , in a fourth step (13) following the third step, a final cleaning is carried out.
  10. Procedure according to Claim 8 or 9 , whereby the etching is carried out as plasma etching.

Description

The invention relates to a seal, for example for a wheel bearing, a gearbox, an e-bike, a wind turbine, or an agricultural machine, made of an elastomer, such as rubber, for example NBR, with an outer surface for contact with a sealing partner, wherein a friction-reducing geometric structure is introduced into the outer surface by means of etching. The invention also relates to a method for surface treatment of an outer surface of a seal. The printed material is state-of-the-art. US 4,667,968 A The publication discloses an improved double-lipped grease-retaining and dirt-exclusion shaft seal. The sealing element comprises a one-piece metal housing with a cylindrical bore sealing section and a radial flange, and a molded elastomeric element connected to the metal housing to provide a section connected to the radial flange and an outer, substantially cylindrical section connected to the surface of the bore sealing section, providing a series of spaced, inwardly projecting retention sections. The elastomeric element also has two diverging lip sections with a cavity between them, one of which provides a grease-retaining lip with small, spaced-apart shallow depressions that allow the passage of small quantities of grease into the cavity, while the other lip section is provided with an attached polytetrafluoroethylene insert. A one-piece metal wear sleeve element has a cylindrical shaft engagement section into which the lips engage, and a radially outward-extending flange with an axially inward-facing section. This outer section is spaced radially inward from the outer, generally cylindrical, section of the elastomeric element, but extends radially outward beyond the radially inner ends of the retaining sections. The publication further discloses that surface areas of the washer are pre-treated, for example, by acid etching and subsequently with a bonding agent to improve the bonding of the elastomer to it. The printed matter DE 3 506 696 C1 Disclosure reveals a lip seal with a metallic housing ring. In this lip seal with a metallic housing ring, the sealing element consists of a cylinder made of PTFE material, the cylinder having two cylindrical sections with different diameters. One section forms the dynamic sealing lip and rests with its circumferential surface against the machine part to be sealed, while the second section forms the connecting element and is joined to an axial leg of the housing ring by clamping, bonding, and/or vulcanization. The ring can be manufactured cost-effectively with low material consumption in simple steps and, due to the constant connection between the PTFE cylinder and the housing ring, offers improved sealing performance combined with high wear resistance. Furthermore, it is generally known that bearing friction occurs in bearings, and especially in wheel bearings, which is often very high and depends on the dynamics of speed and load, tilting, and misalignment due to installation. The bearing's no-load friction depends on the amount of lubricant, the speed, the operating viscosity of the lubricant, the bearing's run-in condition, and the seals. The ratio of frictional power in wheel bearings to heat dissipation from wheel bearings are key parameters that must be considered with regard to the thermally permissible operating number of the wheel bearings. In addition to rolling friction, sliding friction of the rolling elements, sliding friction of the cage, and fluid friction (flow resistance), the frictional power and frictional torques in the bearings are primarily due to sealing friction and, via the frictional heat, determine the thermal degradation of the bearings. This degradation is one of the factors influencing the service life/life of the bearings. Seal friction is significantly influenced by the design and preload of the seal and occurs particularly at the seal of the bearings themselves and/or at the counter-running surfaces. With regard to maintaining competitiveness, and considering the current state of the art, solutions are needed that contribute to a significant reduction in sealing friction in rolling bearings. The requirement for a significant reduction in sealing friction should be understood as reducing the sealing friction to a level relevant for maintaining the competitiveness of seal manufacturers and the industries dependent on them, particularly the automotive supply industry. The present invention aims to achieve an improvement over the prior art. Known disadvantages are to be eliminated or at least reduced. In the case of a seal presented at the outset, this is achieved according to the invention by introducing a friction-reducing geometric structure into the outer surface by means of etching. In other words, the invention relates to a seal with a friction-reducing surface structure. The surface structure is preferably created by etching in the area of the sealing lip contact with the counter-running surface through targeted surface treatment. That is,