Excavator pilot valve group and solenoid proportional valve J225-44A-012000

Excavator Pilot Valve Assembly and Solenoid Proportional Valve J225-44A-012000

The pilot valve assembly is the nerve center of the hydraulic system. Its core function utilizes the pilot stage (pressure-regulating spring/valve core/damping orifice) to achieve 0.1-second pressure fine-tuning. The main valve stage (main valve core/valve seat) uses the pressure differential to open a high-flow channel, forming a precise "small valve controlling a large valve" control architecture. A steady-state closing mechanism balances pressure in the upper and lower chambers when oil enters port P, and the main spring compresses the valve core to isolate the oil circuit. Dynamic self-resets during pressure fluctuations to maintain stable system pressure. The pilot valve outputs pilot pressure oil to drive the proportional valve, which in turn adjusts the main pump flow, forming a three-stage control chain: "pilot pressure → proportional valve → main pump." Do not arbitrarily adjust the proportional valve adjustment screw; comprehensive fault analysis using a computer pressure gauge and electrical signals is required. When disassembling or installing the pilot valve, mark the piping and use fiber-free sealing tools.