VDR-1A-1A2-22 Nachi Variable Vane Pump 16.7cc 14MPa

Product Overview

The VDR series is Nachi’s variable vane pump line, available in single pump (VDR-1A/1B, VDR-2A/2B) and double pump (VDR-11A/11B) configurations. The series employs a unique bias piston mechanism and leak-free pressure balance construction, enabling stable, highly efficient operation at high pressures up to 14 MPa. The VDR series is available in 13 Design and 22 Design versions, with the 13 Design created by modifying some components of the 11/12 designs while maintaining mounting compatibility.

VDR-1A-1A2-22 is a single pump, foot mount, 16.7 cm³/rev displacement, pressure adjustment range 1.5–3.5 MPa, delivering 30 L/min at 1800 rpm. VDR-1B-1A5-22 is a single pump, flange mount, 16.7 cm³/rev displacement, pressure adjustment range 9–14 MPa for high-pressure applications. VDR-11A and VDR-11B are double pump configurations integrating two independent variable vane pumps on a single drive shaft, supplying main and auxiliary circuits, with flows of 30 L/min and 40 L/min respectively at 1800 rpm.

Manufactured to exact Nachi OEM specifications, all mounting dimensions, flange interfaces, and port layouts are fully consistent with the original pump for true drop-in interchangeability. Every unit undergoes 100% simulated operating condition testing before shipment.

Technical Specifications 

VDR Series Common Specifications:

• Series: Nachi VDR Series (Variable Discharge Rate Vane Pump)

• Pump Type: Variable vane pump, pressure compensated

• Control Type: Built-in high-precision pressure compensator, set via adjustment screw

• Pressure Adjustment Range: 1.5–14 MPa (varies by model configuration)

• Allowable Peak Pressure: 14 MPa (143 kgf/cm²)

• Speed Range: 800–1800 rpm

• Rotation Direction: Clockwise (viewed from shaft end)

• Mounting: Foot mount (1A) or flange mount (1B)

• Recommended Fluid: ISO VG32 equivalent below 7 MPa; ISO VG68 equivalent above 7 MPa

• Fluid Temperature Range: 15–60 °C

• Fluid Cleanliness Requirement: NAS Class 10 or better

• Inlet Pressure Range: -0.03 to +0.03 MPa

• Volumetric Efficiency: Leak-free operation via pressure balance construction, minimized power loss at full cutoff

VDR-1A-1A2-22:

• Model: VDR-1A-1A2-22

• Pump Type: Single pump, foot mount

• Displacement: 16.7 cm³/rev

• Pressure Adjustment Range: 1.5–3.5 MPa (15.3–35.7 kgf/cm²)

• Allowable Peak Pressure: 14 MPa (143 kgf/cm²)

• Speed Range: 800–1800 rpm

• No-Load Flow at 1000 rpm: 16.7 L/min

• No-Load Flow at 1200 rpm: 20 L/min

• No-Load Flow at 1500 rpm: 25 L/min

• No-Load Flow at 1800 rpm: 30 L/min

• Weight: Approx. 9 kg

VDR-1B-1A5-22:

• Model: VDR-1B-1A5-22

• Pump Type: Single pump, flange mount

• Displacement: 16.7 cm³/rev

• Pressure Adjustment Range: 9–14 MPa (91.8–143 kgf/cm²)

• Allowable Peak Pressure: 21 MPa (214 kgf/cm²)

• Speed Range: 800–1800 rpm

• No-Load Flow at 1800 rpm: 30 L/min

• Weight: Approx. 9 kg

VDR-11A:

• Model: VDR-11A

• Pump Type: Double pump, foot mount

• Displacement Configuration: Dual pump integrated (specific displacement depends on head side and shaft side configuration)

• No-Load Flow at 1800 rpm: 30 L/min (head side)

• Pressure Adjustment Range: 1–14 MPa depending on configuration

• Allowable Peak Pressure: 14 MPa (2030 psi)

• Speed Range: 800–1800 rpm

• Weight: Approx. 17 kg

VDR-11B:

• Model: VDR-11B

• Pump Type: Double pump, flange mount

• Displacement Configuration: Dual pump integrated (specific displacement depends on head side and shaft side configuration)

• No-Load Flow at 1800 rpm: 40 L/min (head side)

• Pressure Adjustment Range: 1–14 MPa depending on configuration

• Allowable Peak Pressure: 14 MPa (2030 psi)

• Speed Range: 800–1800 rpm

• Weight: Approx. 17 kg

VDR Series Model Code Explanation:

Using VDR-1A-1A2-22 as an example:

• VDR: Series name (Variable Discharge Rate Vane Pump)

• 1: Pump size (1 = single pump size 1, 2 = single pump size 2, 11 = double pump)

• A/B: Mounting method (A = foot mount, B = flange mount)

• 1A2: Ring/head side specification (1 = ring size 1, A = constant discharge characteristic, 2 = pressure adjustment range code)

• 22: Design number (22 = 22 Design Series, medium-high pressure version; 13 = 13 Design Series, low-pressure version)

Key Technical Advantages

1. Bias Piston and Pressure Balance Construction for High-Pressure Efficient Operation: The VDR series’ core technical advantage is its unique bias piston mechanism and leak-free pressure balance construction. The biased piston effectively minimizes ring vibration, and the pressure balance construction eliminates internal leakage paths, enabling highly efficient high-pressure operation with stable performance up to 14 MPa. This design gives the VDR series a significant high-pressure adaptability advantage over comparable variable vane pumps.

2. High-Precision Instantaneous Response with Pressure Compensation Control: The VDR series uses a unique bias piston mechanism that significantly improves pump response. Prompt response is achieved at both ON-OFF and OFF-ON transitions, enabling instantaneous, stable, high-precision operation. The built-in high-precision pressure compensator automatically adjusts displacement based on system pressure. When system pressure reaches the set value, the cam ring automatically shifts to the center position, reducing discharge to minimum. This prevents oil temperature rise, eliminates the need for relief and unloading valves in the circuit, and achieves energy-efficient economic operation.

3. Low Noise Design with 3-Point Support System: The VDR series employs quiet journal bearings, a 3-point ring support system using bias pistons, and improved suction and discharge port shapes to significantly reduce operating noise. Silent, vibration-free operation is ensured even in the high-pressure range, making the series suitable for injection molding machines, machine tools, and applications with strict noise requirements.

4. Reduced Power Loss and Energy-Saving Design: Through a combination of Nachi-original mechanical innovations and precision machining, the VDR series minimizes power loss, especially at full cutoff. Pump output flow is automatically adjusted based on system pressure demand, delivering flow only as needed and avoiding the energy waste caused by excess flow passing through relief valves in fixed-displacement systems. This results in lower system oil temperatures and higher energy efficiency.

5. Solid Construction with Long Service Life: The VDR series pump body is manufactured from high-strength cast iron, with critical running surfaces using carefully selected materials and meticulous machining for excellent wear resistance and long service life. The 3-point support system using bias pistons ensures stable ring operation, reducing abnormal wear on sealing surfaces. Under normal maintenance conditions, the pump delivers continuous working pressure up to 14 MPa, with peak pressure capability meeting instantaneous demands under heavy-load conditions.

6. VDR Series Drop-In Interchangeability with Complete Series Coverage: The VDR series covers both single pump (VDR-1A/1B, VDR-2A/2B) and double pump (VDR-11A/11B) configurations, with the 13 Design and 22 Design maintaining mounting compatibility. Pumps of different sizes within the series share highly consistent mounting flanges, shaft ends, and ports, enabling drop-in replacement without piping or coupling modification — dramatically reducing equipment downtime.

Application Areas

• Injection Molding and Die-Casting Machines: Hydraulic power sources with pressure compensation for energy-efficient operation

• Machine Tools: CNC machine tools, machining centers, grinding machines — hydraulic power units

• Forging Equipment: Hydraulic presses, stamping machines

• Construction Machinery: Small loaders, excavators — auxiliary hydraulic systems

• Agricultural Machinery: Tractor auxiliary hydraulic systems, harvester hydraulic control circuits

• Industrial Hydraulic Systems: Various industrial hydraulic equipment requiring variable vane pumps

• Hydraulic Test Equipment: Test stand hydraulic power sources

• Food Packaging Machinery: Packaging machinery hydraulic drives

Expert Maintenance Tips

1. Shaft Alignment Requirements: Eccentricity error between the pump and drive shaft must be less than 0.05 mm, with angular error less than 1°. The pump mounting base must have sufficient rigidity to prevent housing and bearing stress from base deformation. Install with the pump shaft horizontal.

2. Initial Start-Up Filling and Bleeding: The VDR series pump has no oil filler port. During initial start-up, repeat motor inching (start-stop) operations to allow the pump to draw oil and expel air from the pump interior and suction piping. If air bleeding is difficult, install an air bleed-off valve in the circuit. When oil temperature is below 15 °C at startup, warm the oil or run at low pressure until oil temperature reaches 15 °C or above.

3. Pressure Adjustment Operation: Clockwise rotation of the adjustment screw decreases discharge flow and pressure; counter-clockwise rotation increases them. Loosen the lock nut before adjustment and retighten it after adjustment is complete. Setting pressure may drift due to operating environment and component break-in — periodically verify and adjust the setting pressure.

4. Fluid Cleanliness and Filter Management: Use ISO VG32 equivalent below 7 MPa or ISO VG68 equivalent above 7 MPa, with viscosity index of 90 or higher. Use a suction strainer with filtration of approximately 100 μm (150 mesh) and a 25 μm line filter in the return line to the tank. Maintain fluid contamination at NAS Class 10 or better, and watch for water and foreign matter contamination or oil discoloration.

5. Case Drain Line Configuration: Drain piping must be direct piping up to a point below the tank fluid level, with back pressure due to pipe resistance not exceeding 4.35 psi (approximately 0.3 bar). The drain line inner diameter must be sufficient to ensure unobstructed drainage during cold-start high-viscosity conditions.

6. Drive Method Notes: Avoid drive methods such as belt drive or gear drive that impose radial and thrust loads on the pump shaft end. When using direct coupling drive, ensure proper coupling alignment. Flexible couplings can compensate for minor angular misalignment.