When Doosan excavator's main pump on the upper car body sends oil to the traveling motor on the lower car body, the upper and lower car bodies will make relative rotations. In order to prevent the hydraulic hose from twisting, a center swivel joint is installed in the center of the car body.
working principle
As shown in the figure, the center swivel joint is composed of a shell and a mandrel. The shell is installed on the lower body and the mandrel is installed on the upper body.
A ring-shaped groove equal to the number of pipes is opened on the mandrel. The hydraulic oil from the inlet of the mandrel is supplied to the traveling motor from the vertical holes on the housing through these oil grooves.
Even if the mandrel rotates continuously with the upper car body, the groove on the shell remains unblocked with the oil port on the mandrel, allowing the hydraulic oil to enter and exit freely.
