Oil seals close spaces between moving or stationary mechanical components to prevent lubricants like grease and oil from escaping, while also preventing dust, dirt, moisture, and other contaminants from entering the seal. Also known as shaft seals, dirt seals, lip seals, or grease seals, the primary components of any oil seal include an inner metal ring, which provides structural support, and a spring, which provides interference for effective sealing.
The outer part of an oil seal is made of metal or rubber, depending on the intended application. Metal-cased seals are a cost-effective option used when the housing bore is made of the same material, allowing for equal expansion and contraction of the materials during use. Rubber-cased oil seals provide a tight fit and are commonly used when metal-cased seals have the potential to fail. They are corrosion-resistant and capable of withstanding extreme temperatures and pressures.