Product Overview
The GSP2-16R-A0-947-0, GSP2/16R, and GSP2-A0SI2A06AR-AO-90 are representative models of the UCHIDA GSP2 series external high-pressure gear pumps. UCHIDA is a renowned Japanese pump manufacturer with extensive applications in the construction machinery sector. UCHIDA was later acquired by Bosch Rexroth, and the series is now marketed globally under the UCHIDA-REXROTH brand.
The GSP2 series is a key member of the UCHIDA gear pump product line, offering displacements from 4.5 to 22.4 cc/rev (across six sizes: 04/06/08/12/16/22). The series features a Side-floating System design that maintains optimal gear side clearance regardless of pressure variations, ensuring high efficiency across all operating conditions. The housing mating surfaces utilize parallel pin positioning, making disassembly, reassembly, and maintenance straightforward. The GSP2 series supports a wide range of options including foot and flange mounting accessories as well as tandem pump configurations. The external gear pump can be used continuously at a high pressure of 25 MPa.
Engineered as a direct OEM-replacement solution, these models fully comply with UCHIDA original design standards and mounting interface specifications, offering 100% direct interchangeability with OEM pumps. Every unit undergoes 100% workload simulation testing prior to shipment, rigorously validating pressure retention, volumetric efficiency, and internal leakage performance to meet or exceed OEM standards.
Model Code Breakdown (Bulleted List) :
GSP2-16R-A0-947-0
GSP2 — Series: UCHIDA GSP2 External Gear Pump
16 — Size: Size 16 (16.2 cc/rev displacement)
R — Rotation: R = Right-hand (clockwise, viewed from shaft end)
A0 — Mounting and flange configuration code
947 — Specific configuration code (port specifications, shaft type, etc.)
0 — Suffix configuration code
GSP2/16R
GSP2 — Series: UCHIDA GSP2 External Gear Pump
16 — Size: Size 16 (16.2 cc/rev displacement)
R — Rotation: R = Right-hand (clockwise, viewed from shaft end)
GSP2-A0SI2A06AR-AO-90
GSP2 — Series: UCHIDA GSP2 External Gear Pump
A0 — Mounting and flange configuration code
SI2A — Shaft and seal configuration code
06 — Size: Size 06 (6.5 cc/rev displacement)
AR — Rotation: AR = Right-hand (clockwise)
AO-90 — Specific configuration and pressure level code
Technical Specifications
GSP2 Series General Specifications
Series: UCHIDA-REXROTH GSP2 External Gear Pump
Pressure Rating: Rated 25 MPa (approx. 250 bar), Instantaneous peak 28 MPa (approx. 280 bar)
Displacement Sizes: 04 (4.5 cc/rev) / 06 (6.5 cc/rev) / 08 (8.6 cc/rev) / 12 (12.1 cc/rev) / 16 (16.2 cc/rev) / 22 (22.4 cc/rev)
Maximum Speed: 2500 min⁻¹ (sizes 04–16) / 2000 min⁻¹ (size 22)
Minimum Speed: 500 min⁻¹ (sizes 16–22)
GD² × 10⁻⁴ kgf·m² (Single Type): 04: 0.9 / 06: 1.1 / 08: 1.3 / 12: 1.7 / 16: 2.1 / 22: 2.7
GD² × 10⁻⁴ kgf·m² (Tandem Addition): 04: 1.0 / 06: 1.2 / 08: 1.4 / 12: 1.8 / 16: 2.2 / 22: 2.8
Weight (Flange Mount Type): 5.0 – 6.1 kg
Weight (Foot Mount Type): 1.8 kg
Housing Material: Cast iron
Sealing System: Side-floating System
Positioning: Parallel pin positioning
Recommended Media: Petroleum-based hydraulic oil
Operating Temperature Range: -25℃ to 90℃
Viscosity Range: 10 – 1000 mm²/s
Filtration: NAS1638 Class 9 or better, β10 ≥ 75
GSP2-16R-A0-947-0 / GSP2/16R Specific Specifications
Model: GSP2-16R-A0-947-0 / GSP2/16R
Size: 16
Displacement: 16.2 cc/rev
Rated Pressure: 25 MPa (approx. 250 bar)
Instantaneous Peak Pressure: 28 MPa (approx. 280 bar)
Maximum Speed: 2500 min⁻¹
Minimum Speed: 500 min⁻¹
Rotation Direction: Right-hand (clockwise, viewed from shaft end)
GD² × 10⁻⁴ kgf·m² (Single Type): 2.1
Weight (Flange Mount Type): 5.5 kg
Weight (Foot Mount Type): 1.8 kg
GSP2-A0SI2A06AR-AO-90 Specific Specifications
Model: GSP2-A0SI2A06AR-AO-90
Size: 06
Displacement: 6.5 cc/rev
Rated Pressure: 25 MPa (approx. 250 bar)
Instantaneous Peak Pressure: 28 MPa (approx. 280 bar)
Maximum Speed: 2500 min⁻¹
Minimum Speed: 900 min⁻¹
Rotation Direction: Right-hand (clockwise)
GD² × 10⁻⁴ kgf·m² (Single Type): 1.1
Weight (Flange Mount Type): 5.0 kg
Key Technical Advantages
1. Side-floating System – High Efficiency Across the Full Pressure Range
The GSP2 series features UCHIDA’s proprietary Side-floating System design, which automatically maintains optimal gear side clearance regardless of system pressure variations. This ensures high volumetric efficiency across the full operating pressure range, effectively minimizing internal leakage and reducing energy losses.
2. 25 MPa Continuous High-Pressure Capability
The external gear pump can be used continuously at 25 MPa (approx. 250 bar), with instantaneous peak pressures up to 28 MPa (approx. 280 bar). The high-strength cast iron housing and precision-ground gears ensure long-term operational reliability under high-pressure conditions.
3. Parallel Pin Positioning – Easy Maintenance
The housing mating surfaces utilize parallel pin positioning, ensuring precise alignment upon reassembly after every disassembly. This design significantly simplifies repair and maintenance operations, reducing on-site service time and complexity.
4. Rich Configuration Options & Tandem Pump Support
The GSP2 series supports a wide range of accessories including foot mount and flange mount configurations. Tandem pump configurations are also supported, allowing multiple pump stages to be combined in series to meet the oil supply requirements of multi-circuit hydraulic systems.
5. Wide Displacement Coverage & Flexible Selection
The GSP2 series offers six displacement options from 4.5 cc/rev to 22.4 cc/rev (sizes 04/06/08/12/16/22). GSP2-16R-A0-947-0 (16.2 cc/rev) and GSP2-A0SI2A06AR-AO-90 (6.5 cc/rev) cover medium and small displacement ranges respectively, suitable for hydraulic systems with varying flow requirements.
6. OEM-Proven Reliability & Wide Application Validation
UCHIDA pump products are extensively used in the construction machinery sector. The GSP2 series is widely used as OEM components for XCMG cranes, forklifts, and other leading equipment brands, demonstrating proven reliability in the most demanding work cycles.
7. 100% Factory Tested & Direct Interchangeability
Every unit undergoes 100% workload simulation testing prior to shipment, covering pressure retention verification, internal leakage detection, and flow validation. Fully compliant with UCHIDA-REXROTH original design standards, with flange dimensions, shaft specifications, and mounting interfaces identical to OEM pumps—direct drop-in replacement with zero modifications required.
Application Areas
The GSP2 series gear pumps are widely used in the following equipment:
Construction Cranes: XCMG cranes and other construction lifting equipment hydraulic systems
Forklifts: Hydraulic lifting systems, steering systems
Construction Machinery: Excavators, loaders, and other mobile machinery hydraulic systems
Industrial Hydraulic Systems: Hydraulic power units for various industrial equipment
Agricultural Machinery: Tractors, combine harvesters, and agricultural equipment
Expert Maintenance Tips
1. Model Confirmation
The GSP2 series includes multiple displacement sizes (04/06/08/12/16/22) and configuration combinations. Before installation, verify the complete model code on the original pump nameplate—pay special attention to size code (04/06/08/12/16/22), rotation direction (R=Right/L=Left), and mounting configuration.
2. Rotation Direction Confirmation
Suffix “R” indicates right-hand rotation (clockwise, viewed from shaft end)
Suffix “L” indicates left-hand rotation (counter-clockwise, viewed from shaft end)
Before installation, always verify that the PTO rotation direction of the host machine matches the pump’s rotation direction—incorrect rotation will result in pump failure to prime and may cause severe damage to gears and bearings within a short period.
3. Installation Precautions
Thoroughly clean the mounting flange and shaft mating surfaces before installation to ensure no debris remains
Use UCHIDA-REXROTH-specified torque values for mounting bolts—avoid over-tightening which may cause housing distortion
Ensure correct connection of inlet and outlet ports
The inlet line must have adequate diameter to prevent starvation or cavitation
4. First Start-Up and Bleeding
Before first start-up, must fill the pump with hydraulic oil through the inlet port—never start dry
After start-up, run at low speed with no load for 2–3 minutes to ensure complete air evacuation from the system
Check for abnormal noise or leakage
5. Fluid and Filtration
Use petroleum-based hydraulic oil
Maintain operating temperature within -25℃ to 90℃
Maintain viscosity within 10 – 1000 mm²/s
Maintain system oil cleanliness to NAS1638 Class 9 or better, with filtration β10 ≥ 75
Regularly replace return line filters to prevent contaminants from entering the pump
6. Periodic Maintenance
Check mounting bolt torque every 1,000 operating hours
Regularly monitor system operating pressure—not to exceed 25 MPa rated pressure (28 MPa peak)
The GSP2 series features parallel pin positioning on housing mating surfaces, ensuring precise alignment upon reassembly after maintenance
If flow output decreases, noise levels increase abnormally, or system temperature rises excessively, inspect and replace worn components promptly
