Nachi VDC Series Variable Displacement Vane Pump | VDC-1B-1A2 1A4 2A3

The VDC Series high-pressure variable displacement vane pumps manufactured by Chengyuan Hydraulic are high-precision fluid power units engineered to cross-reference the exacting industrial standards of Nachi (Fujikoshi). This high-efficiency product lineup is meticulously adapted for models VDC-1B-1A2-20, VDC-1B-1A4-20, VDC-1B-1A5-20, VDC-1B-2A2-20, and VDC-1B-2A3-20.

Operating as an energy-saving pressure-compensated power source, the VDC series dynamically alters its internal stator eccentricity in response to system pressure demands, drastically reducing parasitic heat generation and horsepower waste. Chengyuan ensures 100% original-place interchangeability regarding mounting configurations, shaft criteria, and flow-pressure envelopes. Prior to dispatch, every pump undergoes 100% simulated full-load operational condition testing to guarantee steady performance and minimal flow ripple in CNC machine tools and automated factory production lines.

Technical Specifications :

• Brand Compatibility: Nachi VDC Series Replacement (Frame Size 1B)

• Model Classifications Covered: VDC-1B-1A2-20, VDC-1B-1A4-20, VDC-1B-1A5-20, VDC-1B-2A2-20, VDC-1B-2A3-20

• Geometric Displacement Range: 22.0 $cm^3/rev$ to 26.4 $cm^3/rev$

• Rated Operating Pressure: 140 bar (2030 PSI)

• Peak Intermittent Pressure: 175 bar (2538 PSI)

• Pressure Adjustment Codes:

  • 1A Class: Low-pressure settings (e.g., 1A2: 20-35 bar; 1A4: 50-70 bar; 1A5: 70-90 bar)

  • 2A Class: High-pressure settings (e.g., 2A2: 20-35 bar; 2A3: 35-70 bar)

• Permissible Speed Matrix: Minimum 800 rpm, Maximum 1800 rpm

• Control Typology: Hydrostatic Pressure Compensation

• Mounting Standard: SAE A 2-Bolt Flange with a Straight Keyed shaft

• Unit Weight: Approximately 16.5 kg

Key Technical Advantages:

• Dual-Stage Internal Cartridge Architecture: The VDC pump incorporates a specialized internal layout containing cascaded dual-vane sets. This design evenly distributes the intense radial hydraulic forces generated under medium-to-high pressures. It enables the unit to consistently sustain 140 bar operation, a threshold that often causes premature wear in standard single-stage vane pumps.

• Ultra-Responsive Pressure Compensation: Built with a precision spring-loaded plunger mechanism that instantly registers load feedback at the P-port. Once the pre-set pressure limit is crossed, the stator shifts toward the concentric position in less than 0.05 seconds, halting flow output to bare minimum cooling leakage and maximizing electrical energy savings.

• Intra-Vane Structure & Low-Noise Emission: Utilizing a specialized “mother-daughter” dual-vane setup, the fluid forces underneath and on top of the vanes are balanced automatically. Working in tandem with fluid-dynamic optimized timing plates, pressure spikes are softened, bringing full-load operating noise down to $\le 63$ dB(A) for quiet industrial spaces.

• High-Density Anti-Wear Cast Iron Frame: The core pump housing is cast from high-density, anti-friction iron, paired with heavy-duty copper-alloy sliding journal bushings. This metallurgy handles shear forces caused by cyclic pressure changes better than aluminum-body alternatives, extending the pump’s lifecycle by up to 40%.

Application Areas:

• Precision Metal Cutting Machine Tools: Supplies power to CNC turret locking mechanisms, spindle chucking cylinders, and tool post regulators.

• Molding & Footwear Manufacturing Equipment: Serves as the primary power unit for light-industry clamping presses, requiring prolonged high-pressure holding states.

• Automated Assembly Line HPUs: Powers robotic lifting cylinders, pneumatic-hydraulic boosters, and rapid workpiece clamping loops.

Expert Maintenance Tips:

• Mandatory Housing Pre-Fill Mandate: Prior to initial startup or after a long storage period, fill the pump housing with clean hydraulic oil through the top casing port and rotate the shaft manually. Running a variable vane pump dry will cause instant scoring between the rotor, vane tips, and side plates.

• Initial Pressure Adjust Procedure: For setups utilizing 1A4 or 2A3 pressure compensators, back out the adjusting screw counter-clockwise before turning on the motor. Start the system under low pressure until air pockets purge and the fluid warms to 40°C–50°C, then slowly dial the screw clockwise to your target setting.

• Rigid Case Drain Configuration: Internal bypass oil in the VDC series is critical for lubricating internal bearings. You must plumb a dedicated, un-restricted case drain line directly back to the reservoir below the oil level. Ensure casing backpressure never exceeds 0.3 bar to protect the shaft seal from external leakage.