The central rotary joint is composed of the shell and the mandrel. The mandrel is installed on the lower body, while the shell is installed on the upper body. The mandrel is provided with an annular groove equal to the oil pipe. The liquid self-pressure oil from the main spool flows to the motor through the vertical hole in the spindle through the housing, and the housing rotates continuously with the upper body. The groove on the spindle can also keep smooth with the oil outlet on the housing, and the hydraulic oil can flow in and out freely on the central joint.

If not timely replacement of liugong excavator parts of hydraulic oil filter, could lead to filter on the bypass valve opens, the hydraulic oil without oil filter makes the complex degree of qualitative directly into the center of the swivel joint sliding surface, on the sealing ring damage, videotapes excavator caused by the pressure oil leakage on one side of the walk on both sides of the motor speed, the result is to avoid wandering. The elimination method is: when replacing the oil on the center rotary joint, replace the hydraulic oil and the filter channel at the same time.

Use model：922D