Disk blade bearings for agricultural tillage and planting equipment are subjected to high loads in a severe environment. Bearing seal failure leading to premature bearing failure has been an ongoing problem. For years, the main attempt at a solution to the problem has been the utilization of a grease fitting with frequent scheduled greasing to flush contaminates out of the bearing. For most disk gang bearing applications, frequent greasing has been a generally acceptable practice since each bearing normally supports from three to six blades and the grease fittings are reasonably accessible. However, the frequent greasing is time-consuming and reduces the productivity of the implement.
Recently developed combination tillage tools have employed individually mounted bearing blade assemblies, and machines with individually mounted blades are able to run in wetter fall soil conditions. The individually mounted blades create two new problems relative to the grease method of flushing the bearings. First, wetter field conditions are harder on the seals. Mud packs into the seal area and ultimately works into the bearing to cause permanent damage to the seals. To overcome the mud problem, the frequency of required re-greasing to flush the contaminates and prevent bearing failure has to be increased. In addition, the individually mounted blade bearing assemblies result in more bearings to carry the same number of blades as a disk gang. The combination of more grease fittings to grease and an increased maintenance frequency results in a difficult, time-consuming maintenance chore.
Disk mounted bearings require a dust cap on the disk hub which hampers blade scouring and the taper roller bearings must be carefully torqued during the assembly process. The taper roller bearings also act like a pump to force grease out of the raceway and through the seal. The single seal often fails to adequately protect the bearings from contamination by dirt and debris.