The seal shown in Fig. 14.2 is a relatively simple design; most automotive seals are more complex. Dust lips are often used to keep outside contaminants away from the oil lip seals; such seals thus have undercuts that make demolding more difficult. Fluoroelastomer compounds used for such undercut shapes must have reasonably high elongation at break at molding temperatures to avoid tearing the part during demolding. The metal insert is often U-shaped, and stock may be molded to form a thin layer over the outside of the insert. Since both compression and injection molding methods are used, suppliers of fluoroelastomers for shaft-seal applications often must provide different versions of the same polymer composition-medium to high viscosity for compression molding, and low to medium viscosity for injection molding. Different precompounds may be necessary to accommodate relatively long compression-molding times at low temperature and very short injection-molding times at high temperature.

Oil seals are available in an immense range of sizes, for shafts from a few millimetres to several metres. Once the shaft diameter, groove diameter (housing diameter) and groove width are known, selecting an appropriate oil seal is a simple task. An oil seal or its product description is usually associated with three dimensions, for example 6x15x4. These refer to the sizes of the hardware for which the oil seal is designed. In this example, this oil seal is suitable for: 6-mm shaft diameter x 15-mm groove diameter x 4-mm minimum groove width.

The design and material of a shaft oil seal are crucial factors in determining its effectiveness and durability. High-quality seals are made from durable materials that can withstand high temperatures, pressures, and speeds. They are also designed to maintain a tight seal against the shaft while allowing for smooth rotation without excessive friction or wear.

An oil seal serves three crucial purposes within any machinery. First, it prevents the leakage of lubricants or fluids outside the seal, even under high pressure. This function ensures the effective operation of equipment, as sufficient lubrication is a key requirement for the smooth functioning of machinery. Second, it retains the lubricating oil within the machinery. This retention function reduces the need for constant maintenance or re-lubrication, saving time and resources. Third, the oil seal acts as a barrier against contaminants. It prevents dirt, dust, and other potential contaminants from entering the machinery, protecting sensitive parts from damage or wear.

In situations where the shaft has splines or an integral gear on the end, you’ll want to take precautions. These gears and splines often have very sharp edges that are quite detrimental to the seal’s integrity. You may use an installation sleeve that will allow the seal to slide past these hazards undamaged.

: the metal case supports the rotary shaft seal, ensuring the structural stability.

Car Spark Plug: Importance and Impact on Engine Performance

To act as a barrier and prevent dirt, contamination and other external entities from entering the system containing the lubricating oil.

In general, oil seals should be selected in the order of priority indicated in Table 1.