SGP Series SGP1A27A2H9 SGP1A31.9D2H1-L SGP2A52L723 Hydraulic Gear Pump

The SGP1 and SGP2 Series heavy-duty high-pressure gear pumps manufactured by Chengyuan Hydraulic are premium fluid power solutions fully engineered to meet the industrial and mobile vehicle standards of Shimadzu. Featuring the classic three-piece composite construction (high-tensile cast iron gear body paired with lightweight, durable aluminum covers), this series is tailored to withstand rigorous repetitive hydraulic impulses. For precise model codes like SGP1A27A2H9, SGP1A31.9D2H1-L, and large-displacement configurations like SGP2A52L723, we incorporate proprietary hydrostatic axial clearance balancing technology. Every pump undergoes 100% simulated multi-circuit full-load testing (up to 1 million impulse fatigue cycles under 24.5 MPa) before shipment. This ensures volumetric efficiency is sustained above 93%, delivering guaranteed 100% original-place interchangeability.

Technical Specifications :

• Core Model Catalog: SGP1A27A2H9 / SGP1A31.9D2H1-L / SGP2A52L723

• Displacement Range: SGP1 Series: 16.2 to 36.6 $cm^3/rev$ (SGP1-27 is 27.8cc); SGP2 Series: 20.3 to 52.8 $cm^3/rev$ (SGP2-52 is 52.8cc)

• Nominal Operating Pressure: SGP1 Series: up to 20.6 MPa (206 bar); SGP2 Series (Size 52): 17.2 MPa (172 bar), with lower sizes rated up to 24.5 MPa

• Intermittent Peak Pressure: SGP1 Series: 24.5 MPa (245 bar); SGP2 Series: 20.6 MPa (206 bar)

• Maximum Rated Speed: SGP1 Series: 3000 – 3500 rpm; SGP2 Series: 2200 – 3000 rpm

• Minimum Operating Speed: 400 – 500 rpm

• Inlet Absolute Pressure Range: -0.02 MPa to 0.2 MPa (-2.9 psi to 29 psi)

• Housing Structural Material: Heavy-duty fatigue-resistant cast iron gear chamber body with forged aluminum alloy end covers

• Rotation Direction: R (Clockwise, viewing from shaft end) / L (Counterclockwise)

• Shaft & Mounting Configuration: Standard horizontal 2-bolt mounting flange (H) with SAE 10T/13T splined shaft or straight parallel keyed shaft

Key Technical Advantages:

• Rugged High-Tensile Cast Iron Build: By utilizing premium-grade iron for the central gear housing, the SGP series offers far greater structural rigidity than standard full-aluminum pumps. It prevents microscopic chamber distortion under extreme, instantaneous spikes, completely eliminating body fatigue failure.

• Hydrostatic Pressure-Balanced Side Plates: Floating thrust side plates are overlaid with a proprietary low-friction alloy layer. These plates utilize internal hydraulic balance areas to automatically minimize axial tolerances as system pressures rise, preventing internal slippage even if oil temperatures thin out during extended shifts.

• Heavy-Duty DU Composite Bushings: Equipped with heavy-load integrated DU bushings that support the drive and driven gear shafts. This configuration accommodates immense radial unbalance loads without shaft deflection, lowering dry friction during start-up and prolonging service cycles in high-heat environments.

• Precision-Ground Involute Gear Profiles: Gears are forged from high-alloy steel, precision-machined, and vacuum-hardened to micro-level specifications. The optimized gear geometry reduces trapped fluid traps between teeth, dampening mechanical vibrations and high-pitched hydraulic whine.

Application Areas:

• Material Handling Vehicles: Main hydraulic lift and power steering systems for IC and battery forklifts ranging from 3 to 10 tons.

• Construction Machinery: Travel steering assist, pilot control loops for compact excavators, wheel loaders, and 3-point hitch lift linkages for modern agricultural tractors.

• Specialty Municipal Fleets: Primary hydraulic actuation pump for refuse compactors, roll-off trucks, and street sweepers.

Expert Maintenance Tips:

• Strict Rotation Matching Rule: Because the SGP internal fluid paths and pressure-balanced zones are strictly directional, you must verify the last rotation code letter (L or R) against your prime mover’s output. Never reverse the directional setup, as doing so will instantly rupture the main shaft seal upon startup.

• Initial Seal Pre-Priming: Before mounting the new unit, fill the intake port with clean hydraulic fluid and manually rotate the drive shaft several times. This pre-lubricates the premium shaft seal lip and the internal bushings, preventing initial dry-scoring.

• Rigid Contamination Controls: While the cast iron gear body offers excellent resistance to micro-abrasives, maintaining a filtration level of ISO 4406 19/16 (NAS Class 8) via a $10 \mu m$ absolute return filter is highly recommended to protect the floating side plates from scoring.