



Regular maintenance and inspection of shaft oil seals are essential to ensure their proper functioning and prevent costly downtime and repairs. Signs of a worn or damaged seal include oil leaks, increased noise or vibration, and decreased efficiency. If any of these symptoms are detected, it is important to replace the seal promptly to avoid further damage to the machinery.
FKM or FPM, which is in well-known brand Viton™, can withstand higher liquid temperatures of up to 180 ˚C. FKM is highly resistant to strong acids and bases, as well as to synthetic oils and greases. Glycol-based oil and grease, however, can also damage FKM.
Most effective sealing is obtained with optimum shaft surface finishes. The sealing efficiency is affected by the direction of the finish tool marks and the spiral lead. Best sealing results are obtained with polished or ground shafts with concentric (no spiral lead) finish marks. If you must use shafts with spiral finish leads, they should lead toward the fluid when the shaft rotates.
EPDM oil seals are less common. They are used in solvent, hot water and steam applications, EPDM resists low temperatures down to -50 °C and UV radiation well. Some types of EPDM are also suitable for higher temperatures up to +150 °C. EPDM oil seals are usually available upon request.
Figure 5 explains the JTEKT seal numbering system.
Seal numbers consist of
(1) the seal type code,
(2) the spring code,
(3) the lip type code,
(4) the dimensional numbers, and
(5) the special type code,
and Table 6 shows examples of each of these codes/numbers.