A: Sealed bearing is a metal cover (dust cover) or a rubber ring with a skeleton embedded in the groove of the bearing ring (usually the outer ring), with a small gap or contact with another ring (usually the inner ring) to form a closed structure. Bearing with double-sided sealing can not only keep grease, but also prevent dirt and other foreign matters from entering the bearing and keep rolling body rotating in a clean environment. This kind of bearing is often used in poor use environment, maintenance and maintenance of inconvenient occasions.
Dust cover is a pure metal plate stamping parts, generally fixed on the outer ring, and the inner ring of the inner diameter have appropriate clearance, do not allow contact with the bearing in the cage. The commonly used structure form is rolled edge type dustproof cover, after bearing is filled grease, it is pressed to install dustproof cover, dustproof cover is fixed in the mouth of outer ring with mould deformation. General dust cover is pressed after can no longer take off. If you want to take it off, the dust cover will be scrapped. Because there is a gap between the inner diameter of the dust cover and the inner ring of the bearing, the grease cannot be completely sealed in the bearing, nor can too small dust or foreign matter be kept out, so the sealing effect is smaller. Because the dust cover is pressed in the bearing, the dust cover will rarely fall off, sealed structure is solid, heat dissipation is also better than contact seal.
Bearings with more seal ring form, the most common is a steel plate reinforced rubber seal ring form (skeleton type), divided into contact and non-contact. Non-contact sealing ring and dust cover seal form is relatively similar, the inner diameter of the sealing ring and the outer diameter of the bearing inner ring have appropriate clearance amount, can prevent most grease leakage and large particles of dust into the bearing; Contact sealing ring just as its name implies is the inner diameter of the sealing ring has contact with the outer diameter of the inner ring, this way can more effectively prevent the leakage of grease and prevent external dust and liquid from entering the bearing, but because there is contact, will produce some heat, will wear seriously.