Normal recovery of stick empty bucket recovery: When the stick empty bucket is retracted, the P1 and P2 pumps are combined to supply oil to the large cavity of the stick cylinder. The stick 1 valve is in the retracted position, the stick 2 valve is in the normal regeneration position, the pilot valve of the lock valve is in the right position, the CP2, LCa and LCAT2 check valves are all open, and the rest of the spools are not in the initial position.
Figure 2.11 shows the fluid flow path of the hydraulic system for the recovery of the stick empty bucket:
When the stick is in the empty bucket retracting operation, the pressure oil from the pilot pump is switched from the stick 1 valve pilot port PAal to switch the stick 1 spool to the left position (retracted position); from the stick 2 valve pilot port PAa2 to switch Stick 2 spool is operated to the normal regeneration position; the pilot valve spool is switched to the right position from the pilot oil port PLc2 of the pilot valve of the lock valve, and the CRar spring chamber of the plug-in poppet valve communicates with the leaking oil path, causing it to open .
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 and the hydraulic oil flow Go to the parallel oil circuit P2, open the CP2 and LCa check valves, and enter the stick 1 valve.
After the hydraulic oil from the Pl pump flows into the main control valve, it is divided into the middle return oil path P1 'and the parallel oil path Pl. Due to the switching of the stick 2 spool, the middle 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 merge internally and flow from the Aa port of the main control valve to the large cavity side of the stick cylinder to push the stick back.
The return oil from the small cavity of the stick cylinder enters the Ba port of the main control valve, passes through the poppet valve CRar of the open stick lock valve, and enters the stick 2 valve via the stick 1 valve.
As the stick 2 spool is switched to the normal regeneration position, the passage to the fuel tank will be throttled, the return pressure will increase, the check valve inside the stick 2 spool will open, and the return oil will flow to the large cavity of the stick cylinder. Regeneration function.
When the stick is retracted, there is throttling on the oil return passage to the fuel tank. The pressure in the small chamber of the cylinder is greater than the pressure in the large chamber of the cylinder. The check valve in the spool of stick 2 will be opened, and the return oil will be regenerated to the large cylinder. Cavity to realize the energy recovery from the empty bucket. Due to its own weight, the speed of recovery of the stick is very fast, the oil supply in the large cavity is insufficient, and it is easy to generate a vacuum, so the oil return is regenerated to the large cavity to prevent the suction, and it can also provide work efficiency.
