Excavator can rotate indefinitely, and the chain track is not affected, which is the credit of the central rotary joint of the excavator accessories.
The excavator powertrain is in the upper part of the frame, which is responsible for providing power, while the walking motor of the chassis is driven by the powertrain in the upper part of the frame.
Between the upper and lower frames, the power is transmitted through hydraulic pipelines.
According to the professional Volvo excavator accessories small make up to understand that the excavator is fully hydraulic driven, the engine output end directly drives the hydraulic pump, the hydraulic pump provides power for the whole car, and all the actions of the whole car are hydraulic driven, including the telescopic cylinder, rotary motor and walking motor.
The equipment to control the direction of hydraulic oil is called valve set and distributor, which is completed by the control handle (pilot handle) in the cockpit.
The handle drives the valve group to act, and the valve group controls the direction and flow of hydraulic oil, which controls the action and speed.
Each action of the excavator is completed by the valve group driven by the handle of the excavator accessories.
Except for the walking device, because walking is controlled by the foot, the same principle as the handle.
The upper part of the frame is very easy to understand, because the engine hydraulic pump valve set and other components are on the frame, and each cylinder motor can intuitively see the direction of the hydraulic pipeline.
It's as straightforward as a circuit diagram.
But more abstract is the 360-degree rotation, which is the problem of walking motor drive.
If the hydraulic pipe is connected to the upper and lower frame, you can't do a 360 degree turn because the pipe will be torn.
So this part of the excavator uses a central rotary joint, rather than a hydraulic pipeline to connect.
The output of the valve group is connected with the upper part of the rotary joint through the pipeline, and the corresponding output joint is provided under the frame, and the output joint is connected with the traveling motor through the pipeline.
So no matter how much the upper frame rotates, the motor tubing below doesn't rotate.
In addition, the rotary joint consists of a housing and a shaft, the housing being the input part and the shaft being the output part.
There are oil grooves in the shell, and the axis has corresponding oil holes, and there are seals between each group of oil grooves, so as to ensure that the hydraulic oil does not leak and do not cross talk.
May be said in front of the principle we are more difficult to understand, you can refer to the headphone plug principle, it is easy to understand!
After the earphone is plugged into the device, it can rotate 360 degrees, just like the principle of slip ring. No matter how to rotate, the reed in the socket always keeps good contact with the earphone plug.
So, no matter how to turn the earphone will not affect the sound of the earphone.
Therefore, the central rotary joint of excavator accessories is also the same principle.