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Working principle of excavator slewing bearing support system
The slewing system of an excavator is composed of a slewing hydraulic system and a slewing structure device. The slewing hydraulic system of a medium-sized excavator is generally a valve-controlled slewing motor system. During the slewing action, the driver’s cab, working device and fuel tank of the excavator rotate with the slewing platform.
When the rotation starts, the return switch valve is opened, and the hydraulic system outputs high-pressure oil to drive the rotation motor to rotate. The rotation motor transmits the speed and torque of the motor to the outer ring of the slewing support through the planetary gear reduction mechanism inside the motor to overcome friction torque, wind resistance, etc. Other resistance accelerates the slewing platform and drives the slewing platform to the ideal working position; when slewing brakes, close the return switch, and the hydraulic system outputs braking torque to decelerate the slewing motor, and then control the deceleration and braking of the slewing platform.
The slewing device of the excavator includes two parts: a slewing support device that plays a supporting role and a slewing transmission device that drives the turntable to rotate. Slewing bearing device, also known as slewing bearing or extra large bearing, is an important transmission element connecting two relative rotating parts. On the one hand, it can make the two parts realize relative slewing motion, and on the other hand, it can bear the radial and axial movement of the two parts. Directional load and overturning moment. The slewing support of the excavator is located between the upper platform and the underframe.
The vertical load, horizontal load and overturning moment transmission path of the excavator working device acting on the turntable is: the outer race * rolling element * inner race * lower frame of the slewing bearing. When the slewing reduction gear is engaged with the ring gear under the action of the slewing driving force, the slewing reduction gear rotates in white around the axis of the white body, and at the same time receives the reaction force of the ring gear, and the reaction force is transmitted to the mounting flange of the slewing reducer. On the bottom plate of the slewing platform, the upper slewing platform and the beam frame of the walking device are relatively rotated to realize the slewing movement of the excavator.
