STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP 12 The relation of average pump pressure (PP1 + PP2)/2 and the position of servo piston (9) forms a bent line because of the double-spring effect of springs (4) and (6). The relationship between average pump pressure (PP1 + PP2)/2 and pump discharge amount Q is shown in the figure at the right. If command voltage X sent to PC-EPC valve solenoid (1) increases further, the relationship between average pump pressure (PP1 + PP2)/2 , and pump discharge amount Q is proportional to the pushing force of the PC-EPC valve sole- noid and moves in parallel.
In other words, the pushing force of PC-EPC solenoid (1) is added to the force pushing to the left because of the pump pressure applied to the spool (3), so the relationship between the average pump pressure (PP1 + PP2)/2 and Q moves from ➀ to ➁ in accordance with the increase in X . PC210/240-7K 10-45