STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP 12 (2) PC Valve 1) When pump controller is normal a. When the load on the actuator is small and pump pressures PP1 and PP2 are low ➀ Movement of PC-EPC solenoid (1) The command current from the pump controller flows to PC-EPC solenoid (1).This command current acts on the PC-EPC valve and outputs the signal pressure. When this signal pressure is received, the force pushing piston (2) is changed. On the opposite side to the force pushing this pis- ton (2) is the spring set pressure of springs (4) and (6) and pump pressure PP1 (self pressure) and PP2 (other pump pressure) pushing spool (3).
Piston (2) stops at a position where the com- bined force pushing spool (3) is balanced, and the pressure (pressure of port C ) output from the PC valve changes according to this position. The size of command current X is determined by the nature of the operation (lever operation), the selection of the working mode, and the set value and actual value for the engine speed. Other pump pressure This is the pressure of the pump at the opposite end. For the F pump, it is the R pump pressure For the R pump, it is the F pump pressure PC210/240-7K 10-41