Marine Double-row Ball Slewing Ring

Double-row Ball Type Marine Crane Slewing Bearing

The marine double-row ball slewing ring bearing offers a compact design that reduces the diameter of mounting holes in both the inner and outer rings, while simultaneously increasing the loading capacity.

Typically composed of three rings, this double-row ball slewing ring bearing allows steel balls and spacers to directly enter the upper and lower raceways. The placement of two sets of steel balls is determined through force analysis. This configuration, with 90° bearing angles in the upper and lower arc raceways, enables the bearing to withstand significant axial force and tilting moments.

In cases where the radial force exceeds one-tenth of the axial force, special design considerations are necessary for the raceway to accommodate the additional radial force effectively.

Material Of Marine Double-row Ball Slewing Ring

The marine double-row ball slewing bearing is manufactured with specific materials to ensure optimal performance and durability. The range of external diameter for these bearings is typically between 100 mm and 15,000 mm. The materials used for the different components are as follows:

• Ring Material: The rings are commonly made of 42CrMo, 50Mn, or C45 steel. These materials offer excellent strength, toughness, and resistance to wear and fatigue.
• Ball/Roller Material: The balls or rollers in the bearing are typically made of GCr15 steel. GCr15 is a high-quality bearing steel known for its hardness, wear resistance, and ability to withstand high loads.
• Cage Material: The cage, which holds the balls or rollers in position, can be made of either steel 20 or ZL102 cast aluminum alloy. Steel 20 provides robustness and strength, while ZL102 cast aluminum alloy offers lightweight characteristics and corrosion resistance.
• Spacer Material: Spacers, used to maintain proper spacing between the balls or rollers, are commonly made of nylon 6 or nylon 66. These materials provide good dimensional stability and low friction properties.
• Quenching Hardness of Raceway: The raceway, subjected to quenching during the manufacturing process, typically has a hardness ranging from HRC55 to HRC62. This hardened raceway ensures enhanced durability and resistance to wear.

Marine Double-row Ball Slewing Bearing Applications

The marine double-row ball Slew ring finds extensive application in port machinery, where its robust design and capabilities are highly advantageous. Some common applications of this bearing in port machinery include:

• Cranes: The slewing ring is utilized in various types of cranes used in ports, such as harbor cranes, container cranes, and ship-to-shore cranes. It enables smooth and precise rotation of the crane structure, supporting heavy loads and facilitating efficient cargo handling operations.
• Excavators: In port settings, excavators are employed for tasks like dredging, digging, and material handling. The double-row ball slew ring allows the excavator to rotate smoothly, providing stability and load-bearing capacity during operations.
• Ship Loaders and Unloaders: These machines are responsible for loading and unloading cargo onto and from ships. The slew bearing assists in the rotational movement of the loading/unloading arms, ensuring accurate positioning and efficient transfer of goods.
• Conveyor Systems: Port conveyor systems transport bulk materials, containers, or packaged goods. The double-row ball slew ring enables the smooth rotation of the conveyor structure, facilitating the movement of materials along the conveyor lines.
• Tugboats and Floating Cranes: Tugboats and floating cranes play essential roles in port operations, assisting with berthing, towing, and lifting heavy loads. The slewing bearing supports the rotation of the crane or towing arm, allowing for precise maneuvering and reliable lifting capabilities.

Structure Of Marine Double-row Ball Slewing Ring

The structure of the marine double-row ball slewing ring:

• Inner Ring
• Outer Ring
• Seal
• Spacer
• Ball/Roller

Parameter Of Double-row Ball Slew Ring

No Gear Type Double-row Ball Slewing Bearing

External Gear Type Double-row Ball Slew Ring

Internal Gear Type Double-row Ball Slewing Ring