The function of the Accumulator Charging Valve is to control the charging of the accumulator within a preset switching range.
There are integrations of a pilot stage with defined hysteresis, a main piston, and a check valve into the circuit.
Therefore, the charge of the accumulator happens at port A from pump port P across the check valve. Indeed, if the pressure in the accumulator exceeds the pre-set value of the pilot stage, the main piston opens. Then, relieved of the pump to the tank happens. If the pressure in the accumulator decreases by the value of the switching pressure differential, the pilot stage closes again. Then, it recharges the accumulator.