Self-aligning ball bearings have two rows of balls and a common sphered raceway in the outer ring; this latter feature gives the bearing its self-aligning property, permitting minor angular misalignment of the shaft relative to the housing. They are therefore particularly suitable for applications where misalignment can arise from errors in mounting or shaft deflection.

HRB self-aligning ball bearings are available with cylindrical or tapered bore. Bearings with tapered bore can be supplied with suitable adapter sleeves.

HRB self-aligning ball bearings are also available with seals (rubbing) at both sides. The seals, of oil and wear-resistant synthetic rubber, seal against recesses in the inner ring shoulders. The bearings are supplied filled with the correct quantity of lithium base grease and can be used at operation temperatures between - 30 and +110℃. Relubrication in service is not required and the bearings should not be washed or heated before mounting.