- The wheel hub oil seal is a vital component in automotive systems, serving as a barrier between the wheel hub and the axle. Its primary function is to prevent the loss of lubricant from the hub bearing, ensuring smooth operation and extended life for this critical part. Additionally, it prevents contaminants such as dirt and water from entering the bearing area, which can lead to premature wear and failure.
In different applications like tyres, belts, and oil seals, situations where resistance to fatigue with improved life span is desired, and in gaskets, and electronic and electrical equipment, conventional type rubbers are reinforced with filler materials to enhance their physical, electrical, thermal, and mechanical properties. Compared to the conventional rubber/rubber composite-reinforced fillers, the addition of nanomaterials has gained extra attention in recent years, and these are called nanocomposites [40,61]. Nanomaterials have unique properties which are changed due to their size reduction in any one dimension, like chemical (reactivity or catalysis), thermal (melting temperature), electronic (electrical conductivity), optical (scattering or absorption of light), or magnetic (magnetization) properties [40]. Among various types of nanomaterials, CNTs are one of the most attractive reinforcements used in the rubber nanocomposites, due to their high aspect ratio, flexibility, diameter in the nano range, and physical, mechanical, and electrical properties along the axis of the tube. MWCNTs have greater advantages than SWCNTs or DWCNTs in the range of possible industrial applications and low production cost, which can also provide similar composite properties [40,62,63]. In nanocomposites, uniform dispersion of the CNTs plays a very important role in increasing the properties of the developed material. This is because of the bonding between the nanotubes being very high and ending up in a cluster formation [63]. In recent research, MWCNTs/SWCNTs were used as reinforcements and mixed with caoutchouc or natural rubber matrix material to obtain an MWCNT/SWCNT–natural rubber nanocomposite (nanostructures), by adding the CNTs into a polymer solution like acetone, dimethyl formamide, toluene, or tetrahydrofuran and mixing either by high-energy sonication, magnetic agitation, or mechanical mixing. Simultaneously, in addition to the poor solution, the solvent gets evaporated and obtains better dispersion of nanotubes. It is a better method to achieve uniform dispersion and distribution of nanotubes into the matrix material. One major constraint for this method is neglecting the improper solubility of polymer into the solvent to carry out the next process [40]. Also, MWCNTs improved the mechanical and electrical properties of other types of rubbers, such as chloroprene, acrylonitrile–butadiene, styrene butadiene rubber, and ethylene–propylene–diene monomer [62].
ERIKS type M (type B according to the DIN standard) has a single metal casing and rubber sealing lip. Since the casing is made of metal, it must be fitted in a well-finished, undamaged groove. Large volumes of oil seals with metal casings are often cheaper, which is why they are often used as original equipment in machines. However, if an oil seal has to be replaced, types with a rubber exterior (type R or RST) are easier to fit. Type MST is similar to M and commonly used. The difference is the dust lip in the MST oil seal that prevents dust and dirt reaching the sealing lip, and extends its service life in dusty environments.

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Other important factors are ensuring the hardness and roughness of the shaft are correct. A shaft hardness of HRC 45 is recommended for a rubber sealing lip, with a roughness of Ra 0.4-0.8. A higher shaft hardness of HRC 60 and shaft roughness of Ra 0.1-0.4 is recommended for a PTFE lip.
Vulcanizates of several fluoroelastomers, listed in Table 14.1, were exposed to a standard 5W-30 engine oil, ASTM Service Fluid 105, for up to 6 weeks at 150°C (302°F).5 The oil was changed weekly, but was not aerated. Retained elongation was measured after exposure for 1, 2, 3, and 6 weeks; data are shown in Fig. 14.3. The results indicate that bisphenol-cured FKM-A500 VDF/HFP copolymer, FKM-B600 VDF/HFP/TFE terpolymer, and peroxide-cured FEPM-7456 TFE/P/VDF terpolymer lost most of their original elongation over the course of the test exposure, indicating considerable additional cross-linking occurred by reaction with amine- and phenol-containing oil additives. The other fluoroelastomers showed better retention of elongation, being much less susceptible to additional crosslinking. Note that FEPM-7456 contains a high level of VDF (about 30%), while FEPM-7506 contains a relatively low VDF level (10–15%) to serve as cure site for bisphenol curing. The other FEPM types contain no VDF.