Hitachi Excavator Parts EX1200-6 ZX850-3 ZX650-3 Hydraulic Main Pump 4635645 K3V280

Hitachi excavator parts EX1200-6 ZX850-3 ZX650-3 hydraulic main pump 4635645 K3V280

We could supply the hydraulic pump and also the inner spare parts as below model:

Closed-Circuit Pump (Axial Piston - Variable Displacement):
Specifically designed for hydrostatic transmissions driving travel motors or sometimes swing motors in excavators, the closed-circuit pump operates fundamentally differently from open-circuit pumps. Its principle involves two integrated variable displacement axial piston units (pump and motor) or one pump unit connected directly to a hydraulic motor via two main lines (A & B). Fluid circulates in a closed loop between the pump and motor. The pump's direction of flow (determining motor rotation direction) is controlled by tilting the swashplate over center (positive or negative angle). Displacement controls motor speed. A small, fixed displacement charge pump (usually a gear pump) is essential. It replenishes minor leakage in the closed loop, provides cooling flow through a flushing valve, and supplies pressurized fluid to the pump's servo control for swashplate movement. Structurally, the main pump section resembles a standard axial piston pump but has two main ports (A & B) instead of dedicated inlet/outlet. It incorporates check valves for charge pressure replenishment and often a flushing valve assembly.