The loading platform for hydraulic excavator maintenance is connected to the lowering base through a slewing support. When working, the upper platform can rotate relative to the lower platform. However, the driving and speed conversion of the walking hydraulic motor use hydraulic oil as the working medium. These working mediums (hydraulic oil) are transmitted from the upper car transmission oil circuit to the lower car transmission oil circuit, which is used by the shell of the central return transfer. The baffle plate is fixed on the loading platform of the slewing center, and the mandrel and flange are fixed on the lowering base of the slewing center with bolts. When the upper platform of the excavator rotates relative to the lower base, the shell of the central rotary joint rotates around the mandrel. The 4 high pressure oil ports (A, Bi, C, D) on the shell, pilot pressure oil port F] and oil drain port T" pass through the annular channel on the inner surface and the 4 high pressure oil ports on the mandrel (A2, B2> C2> D2), oil port F2 and oil port T2 are connected correspondingly. The annular channels are separated by a rectangular rotating oil seal to prevent oil from colluding. The structure of the central rotary joint is shown in Figure 3-31.
1-Upper cover; 2-Shell; 3-Rectangular rotary oil seal; 4-Skeleton oil seal; 5-Mandrel;
Autonomous control valve travel spool Asr port (forward); Autonomous control valve travel spool Ail port (forward); A to right travel motor Pb port (backward); D2—to left travel motor Pa port (forward); Bi— From the main control valve travel spool Bn. port (backward); from the travel speed solenoid valve;
B2—to the left travel motor Pb port (backward); F—to the left and right travel motor P port; G—from the main control valve travel spool B5R:
"One to fuel tank; C2 one to right travel motor Pa port (forward)
