NACHI PISTON PUMP PVK-3B Full Specification
1. Product Introduction
PVK-3B is a compact variable Hydraulic piston pump manufactured by NACHI-Fujikoshi Japan, acting as the main hydraulic pump for 5-6 ton mini excavators. It integrates main pumping unit and pilot gear pump as one assembly, supplying main power and pilot control oil for the whole machine’s complete hydraulic system. The mainstream OEM model PVK-3B-725-N-5074A (Hitachi PN:4668462) is originally equipped on Hitachi ZX60USB-3, ZX65USB-3 tail-less excavators and domestic mini diggers, equipped with constant horsepower & load sensing dual control to stabilize the performance of the entire hydraulic system.
2. Model Definition
- PVK: Special compact piston pump series for mini excavators
- 3B: Pump housing size code for open circuit general mounting
- 725: Max displacement 72cc/rev
- N: NBR rubber seals for standard mineral hydraulic oil
- Suffix code: OEM customized calibration for pressure & flow curve
3. Construction & Materials
1. Heavy-duty cast iron pump housing, anti-shock and anti-vibration for harsh construction sites
2. Internal rotating group: 11pcs hardened pistons & bronze slippers, spherical valve plate, swash plate assembly
3. Integrated main pump + pilot gear pump structure, simplifying piping layout of the hydraulic system
4. Top integrated regulator with constant power & LS load sensing spool
5. SAE involute spline drive shaft for engine connection
4. Technical Parameters
Item Specification
Type Variable Hydraulic piston pump
Displacement 72cc/rev
Rated Pressure 24.5MPa
Max Peak Pressure 27MPa
Rated Speed 2400rpm
Max Intermittent Speed 2600rpm
Built-in Pilot Pump Displacement 8.2cc/rev
Control System Constant Horsepower + LS Load Sensing
Compatible Hydraulic Fluid ISO VG46 / VG68 anti-wear hydraulic oil
Operating Temp -20℃ ~ +90℃
Net Weight 32KG
Application 5~6 ton mini excavator hydraulic system
5. Working Principle
Driven by engine shaft, the cylinder block and pistons rotate to deliver hydraulic oil. The swashplate angle changes to adjust flow output of the hydraulic pump. LS valve detects load pressure in real time to optimize pump displacement; the built-in pilot pump feeds control oil to distribution valves, forming a full functional hydraulic system. Constant power mechanism limits total output under heavy load to prevent engine stall and protect the Hydraulic piston pump.
6. Features & Application
1. All-in-one integrated structure reduces pipeline leakage points of the hydraulic system
2. Spherical valve plate design ensures high volumetric efficiency, low noise and long service life
3. Dual intelligent control balances digging power and fuel consumption for frequent start-stop operation
4. OEM original calibration, plug-and-play replacement without commissioning
- Application: Hitachi, Sany, Yuchai, XCMG 5-6 ton mini excavators, mini breakers’ core hydraulic system power source
- Replacement Scenarios: Replace this hydraulic pump for weak operation, speed drop after heating, abnormal noise and insufficient system pressure caused by worn internal parts of the Hydraulic piston pump
