4,7 tons of heavy spherical bearings for cutting dredgers

schaeffler0919 Schaeffler has manufactured the largest spherical plain bearing to date in the company's history. The special bearing has an outside diameter of 1900 mm, a bore diameter of 1500 mm and a height of 600 mm. The weight is just under 4,7 t. The warehouse is used in a cutter head excavator designed and built by Royal IHC.

The Dutch company specializes in equipment, ships and services for the offshore, dredging and wet decay markets. A cutter dredger is a workboat with or without its own propulsion that releases solid material from water bottoms. Vacuum absorbs the rock and promotes it, inter alia, via floating pipes on land. Particularly stressed is the connection between the pipeline and the ship, which takes place via a mounted on the fuselage pivot bearing. The bearing absorbs the rotational movements that occur between the pipeline and the hull. Based on these requirements, a specific bearing designed for the application was designed.

The bearing was customized in a record time of only three months. The impact loads occurring in the application made a one-piece construction of the inner and outer ring necessary. The bearing must eliminate the edge stresses that occur and absorb large forces corresponding to the dimensions. Because the forces only act on one side of the spherical plain bearing, it was designed asymmetrically. This saves space and weight. A special lubrication groove system guarantees a long bearing life and low wear. The lubrication grooves are designed so that the grease is evenly distributed even with small swivel movements in the range of 20 degrees.

The operating conditions in the offshore area also require special corrosion protection. For this, the sliding surfaces of the bearing were provided with a proven anti-friction varnish. This ensures that even in the case of insufficient lubrication no metallic contact between inner and outer ring is created. Grease lubrication additionally protects the bearing against corrosion.

Another contribution of the manufacturer