TC NBR Skeleton Oil Seal Rings Double Lip Sealing ID 50~400mm for Rotation Shaft

Measure three dimensions: the shaft outer diameter (this becomes the seal ID), the housing bore inner diameter (this becomes the seal OD), and the depth of the seal cavity (this determines the seal height). Match all three to the Size (IDxODxHeight) variant listed above. If your shaft is worn, measure at the unworn section or consult the equipment service manual for the nominal shaft diameter.

TC is a standardized designation for a double-lip radial shaft seal. The primary lip (inner) seals lubricant inside the housing; the secondary lip (outer) acts as a dust and dirt excluder. This two-barrier design makes TC seals suitable for applications where both oil retention and contamination exclusion are required, such as gearboxes, axles, and pump housings.

NBR performs well with conventional petroleum-based oils, mineral hydraulic fluids, and many ATF formulations. It is generally not recommended for use with phosphate-ester hydraulic fluids, ketones, or highly aromatic fuels. If your application uses a fully synthetic ester-based fluid, verify compatibility with the fluid manufacturer's seal material guidelines before installing.

For reliable sealing, the shaft contact surface should have a finish of Ra 0.2–0.8 µm (approximately 8–32 µin) and a hardness of at least 45 HRC to resist lip wear. Avoid lead-in chamfers with sharp edges; a 15°–20° chamfer or radius on the shaft end helps guide the lip over the shaft without folding or cutting it during installation.

Clean the housing bore and lightly lubricate the seal OD with a thin film of the same oil used in the application. Apply light grease to the sealing lip. Use a flat driver or seal installation tool that contacts the outer edge of the seal face evenly — never drive on the rubber lip or the center. Press straight in until the seal face is flush with or just below the housing face. Avoid cocking the seal during installation.

TC NBR skeleton seals are suitable for moderate to medium shaft speeds. As a general guideline, the peripheral shaft speed at the seal lip should not exceed approximately 4–8 m/s for standard NBR lip seals, depending on shaft finish and lubrication. For high-speed applications above this range, consult the equipment OEM specification or consider PTFE-lip variants designed for higher surface speeds.

A single-lip (SC) seal has one sealing element that retains lubricant. A double-lip (TC) seal adds a second, shorter dust lip on the atmosphere side that prevents dirt, water, and debris from reaching the primary sealing lip. TC seals are preferred in environments where the shaft is exposed to contamination — such as agricultural equipment, outdoor machinery, or wet industrial settings — because the dust lip extends the life of the primary seal.