Multi-way valve consists of two sets of valve blocks
Swivel, standby, stick and left travel directional valves are in one valve group, supplied by a pump (PL is the oil inlet); boom, bucket and right travel directional valves are in a valve group, and a pump ( PR is the oil inlet).
Each directional valve is controlled by pilot control oil.
The characteristics of the multi-way valve:
Boom rises and merges, up and down of the stick merge (when the boom is not raised); the boom and stick circuits are respectively equipped with holding valves to prevent natural sliding; the boom down circuit is provided with a regenerative charge circuit (return oil back pressure) Valve + charge check valve), the stick down circuit is equipped with a regenerative charge circuit (return throttle valve + charge check valve) to maintain the continuity of boom and stick down.
Negative flow control valves are installed on the central return passages of the two valve groups. When the spool of the multi-way valve is in the neutral position or the spool is slightly opened, the boom is lowered, or the bucket excavation is blocked, the negative flow control valve is produced. The pressure signal is sent to the main pump, which automatically reduces the displacement of the main pump.
Schematic diagram of Komatsu excavator multi-way valve:
The main oil inlets PR and P1 of the multi-way valve are connected to the connection ports FR and F1 of the negative flow control of the pump, and the connection port R of the return tank; the connection ports AL1, BL1; and AR1, BR1; ... Pilot control oil connection ports al1, bl1; ... and ar1, br; ..., and oil return ports dr1, dr2; ... and pilot control oil to each valve stem. In order to reduce the pipeline, reduce the fluid resistance, and facilitate the connection of the entire oil circuit, some elements belonging to the oil circuit of each hydraulically acting element are also integrated on the valve.
For example: safety valve, overload valve, boom and arm holding valve and regenerative charge valve, etc.
The multi-way valve is only equipped with a main safety valve (Z valve, 32MPa), which controls the maximum working pressure of the boom, bucket, stick and walking; the maximum working pressure of the swing (27.5MPa) is buffered by two swing motors Valve control.
Boom reversing valve, bucket reversing valve and arm reversing valve are each connected in parallel with a pair of overload valves (36MPa), and standby control valves are connected in parallel with a pair of safety valves (20MPa).
