Stick release conditions: The stick release conditions use P1 and P2 double pumps to converge to supply oil to the small cavity of the stick cylinder. The return oil from the large chamber of the cylinder returns to the tank through the stick 1 valve and stick 2 valve. The stick 1 valve and stick 2 valve are both in the stick release position, the pilot valve of the lock valve is in the left position, the CP2, LCa and LCAT2 check valves are all open, and the rest of the spools are not in the initial position.
Note: Orange line is one inlet line; green line is one return line: purple line is one pilot line; blue line is one leakage line; the blank position in the valve is the working position, which will be the same hereinafter.
The flow path of the hydraulic system of the Kobelco excavator stick is shown in Figure 2.10
When the stick release action is performed, the pressure oil from the pilot pump switches the stick 1 spool to the right position (release position) from the stick 1 valve pilot port PBal; the stick 2 valve switches the stick 2 valve from the stick 2 valve pilot oil port PBa2 Work from the core to the release position; there is no pilot pressure oil in the PLc2 port, and the pilot valve works in the left position.
After the hydraulic oil from the P2 pump flows into the main control valve, it is divided into the middle return oil path P2 'and the parallel oil path P2, but due to the switching of the stick 1 spool, the middle return oil path P2 "is cut off from the parallel oil Channel P2 flows in, opens the CP2 and LCa check valves, and flows to the stick 1 valve.
After the hydraulic oil from the P1 pump flows into the main control valve, it is divided into the central return oil path P1 'and the parallel oil path P1. Due to the switching of the stick 2 spool, the central return oil path P1' is closed and the parallel oil input path P1 There is also a throttle valve LCAP2, the hydraulic oil opens the check valve LCAT2, and flows to the arm 2 valve. The oil discharge of the P1 pump and the oil discharge of the P2 pump are merged inside the valve. The poppet CRar of the stick lock valve is pushed open. After CRar, the Ba port of the main control valve flows to the small cavity side of the stick cylinder to push the stick release.
The return oil from the large cavity of the stick cylinder enters the Aa port of the main control valve, flows through the stick 1 valve and the stick 2 valve, and returns to the tank from the return path.
