Slewing Bearings: Core Support for Rotating Functions in Construction Machinery

I. Common Types of Slewing Bearings in Construction Machinery

• Four-point contact ball slewing bearings: They can bear axial loads, radial loads, and overturning moments simultaneously. With a compact structure, they are suitable for rotating mechanisms with medium and light loads.

• Crossed roller slewing bearings: The rollers are arranged in a crossed manner, featuring a large contact angle, high rigidity, and strong load-bearing capacity. They are applicable to equipment with heavy loads and high requirements for rotation accuracy.

• Three-row cylindrical roller slewing bearings: Composed of two rows of axial rollers and one row of radial rollers, they can bear loads in different directions respectively. With extremely strong load-bearing capacity, they are suitable for ultra-heavy machinery.

II.Specific Applications of Slewing Bearings in Construction Machinery

• Excavators: Four-point contact ball or crossed roller slewing bearings are used to connect the upper car body (cab, boom) with the chassis, enabling 360° rotating operations, supporting the weight of the whole machine and bearing the impact force during excavation.

• Tower cranes and crawler cranes: Three-row cylindrical roller slewing bearings are mostly adopted to support the tower body and slewing tower, bear the huge overturning moment generated by the lifting weight, and ensure precise rotation and positioning of the boom.

• Concrete pump trucks: Crossed roller slewing bearings connect the chassis with the boom, enabling flexible extension, retraction, and rotation of the boom to ensure accurate delivery of concrete to the designated position.

• Pile drivers and rotary drilling rigs: They rely on high-load slewing bearings to connect the power head with the frame, bear severe vibration and vertical loads during piling or drilling, and ensure the stable operation of the rotating mechanism.

• Pavers: Four-point contact ball slewing bearings are used to support the rotation adjustment of components such as the screed, ensuring the flatness of road paving.

III.  Core Characteristics of Slewing Bearings in Construction Machinery

1. High load-bearing capacity: They can bear the composite moments (axial, radial, and overturning moments) generated by the equipment's own weight, operating load, and rotation.

2. Strong stability: Maintain stable rotation under complex working conditions (such as vibration, impact, dust, high and low temperatures) to ensure continuous operation of the equipment.

3. High-precision rotation: Ensure precise positioning and 360° all-round rotation of components such as mechanical arms and upper car bodies, improving work efficiency.

4. Long service life: Made of high-strength steel and special heat treatment processes, they are wear-resistant and corrosion-resistant, adapting to the harsh working environment of construction machinery.