It is composed of a turntable, a slewing bearing and a slewing mechanism. The outer ring of the slewing bearing is connected with the turntable by bolts, the inner ring with teeth is connected with the underframe by bolts, and rolling elements are arranged between the inner and outer ring. The vertical load, horizontal load and overturning moment of the excavator working device acting on the turntable are transmitted to the underframe through the slewing bearing. The housing of the slewing mechanism is fixed on the turntable, and a pinion is used to mesh with the inner ring gear of the slewing bearing. The pinion can rotate on its own axis or revolve around the centerline of the turntable. When the turning mechanism is working, the turntable will rotate relative to the chassis.
The excavator has a wide range of uses. It can be equipped with various working devices to perform various forms of earthwork or stonework. In open-pit mining, the excavator can be used for topsoil stripping, dumping, and mining and loading of minerals. In addition, it is also widely used in construction, railway, highway, water conservancy and military engineering.