Excavator K5V140DTP1G9R CX330 hydraulic main pump KSJ2851 KSJ15460 main pump assy kit

The axial piston hydraulic pump is the core component of the main hydraulic system in medium and large excavators. Its design centers on the principle of "reciprocating movement of pistons to change volume". The cylinder block inside the pump is arranged coaxially with the drive shaft, and multiple piston holes are evenly distributed around the circumference of the cylinder block. Each piston in the hole is in contact with the swash plate through a slipper. When the engine drives the drive shaft to rotate, the cylinder block rotates synchronously. Under the combined action of the inclined thrust of the swash plate and the return spring, the piston makes a reciprocating linear movement along the piston hole: when the piston moves from the bottom to the top of the cylinder block, the sealed volume in the piston hole increases, creating a negative pressure, and low-pressure hydraulic oil is sucked from the oil tank through the suction valve; when the piston moves from the top to the bottom, the sealed volume shrinks, the oil is compressed, and the high-pressure oil is discharged through the pressure valve after the pressure rises, finally converting the rotational mechanical energy of the engine into the pressure energy of the hydraulic oil.