For applications in which airborne or fluid contaminants threaten the useful life of spherical or rod end bearings, NHBB offers a combination metal shield and silicone seal to isolate and protect bearing surfaces.
The NHBB sealing system comprises a pair of .010 (Ref.) stainless steel (or any other compatible weldable metal) shields and molded wedge-shaped silicone rubber seals. This seal system design does not significantly increase the weight of the bearing.
The shields are welded to the outer race of the bearing so that the seals are seated at the juncture of the ball and the race. As ball movement occurs, the seals wipe contaminants from the ball surface. This self-cleaning action prohibits most contaminants from reaching the load bearing area. Seals do not reduce the load bearing area or change the load rating of a bearing.
NHBB sealed bearings have been subjected to extensive dynamic testing by major aircraft manufacturers for resistance to contamination by MIL-H-5606 hydraulic oil and SAE AS 8243 de-icing fluid. Sealed bearing wear after 25,000 cycles was considerably less than unsealed bearing wear.
NHBB can seal any size metal-to-metal or self-lubricated bearing. The seal typically does not affect external mounting dimensions or dimensionally affect function on V-groove installations. Form, fit, and function interchangeability are maintained. However, a seal does reduce misalignment capability. NHBB seals can be used with bearings having staking grooves in the outer race, as well as with bearings having chamfered outer race configurations. For information on seal damage prevention when installing in counter bores that may contact the race face, contact NHBB Applications Engineering.