TheKP2D28 Hydraulic Piston Pumpis a high-pressure, high-efficiency positive-displacement hydraulic pump featuring an axial piston design. It achieves hydraulic oil suction and discharge through the reciprocating motion of pistons within cylinders. Suitable for hydraulic systems requiring high pressure, large flow rates, and stable output, it is widely used in construction machinery, industrial equipment, marine applications, metallurgy, and other fields.
Key Advantages:
• High-Pressure Output: Rated pressure up to 28 MPa (4060 psi), with higher peak pressure capability.
• Energy Efficiency: Volumetric efficiency ≥92%, total efficiency ≥85%.
• Variable Displacement: Supports adjustable displacement (e.g., manual, hydraulic, or electronic control).
• Long Service Life: High-strength alloy steel pistons and copper-alloy valve plates for wear resistance and corrosion resistance.
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2. Core Functions
• Hydraulic Energy Conversion: Converts mechanical energy (from motors/engines) into hydraulic energy (pressure and flow).
• Flow Regulation: Achieves stepless displacement adjustment by altering swashplate angle or piston stroke.
• Bidirectional Rotation: Supports forward/reverse operation (requires bidirectional variable mechanism).
• Self-Priming Capability: No external charge pump required (for certain models).
• Overload Protection: Built-in relief valve prevents system overpressure.
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3. Technical Specifications (Typical Values)
【表格】
Parameter KP2D28 Specifications
Displacement 28 cm³/rev (variable range: 14–28 cm³/rev)
Rated Pressure 28 MPa (4060 psi)
Peak Pressure 35 MPa (5075 psi)
Speed Range 600–2000 rpm (dependent on drive power)
Flow Rate 16.8–56 L/min (@28 cm³/rev, 600–2000 rpm)
Drive Power ≤45 kW (@28 MPa, 2000 rpm)
Weight Approx. 25–30 kg (with variable mechanism)
Port Sizes Inlet: G3/4; Outlet: G1 (BSPP)
Noise Level ≤75 dB(A) (at 1 m distance)
IP Rating IP65 (dust/water-resistant)
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4. Structure and Working Principle
Key Components:
1. Cylinder Block: Contains multiple piston bores and rotates coaxially with the main shaft.
2. Pistons: High-precision steel pistons with slipper shoes contacting the swashplate.
3. Swashplate: Fixed or variable angle to control piston stroke.
4. Valve Plate: Distributes inlet/outlet ports for suction/discharge switching.
5. Variable Displacement Mechanism: Manual, hydraulic, or electronic control of swashplate angle.
6. Bearings and Seals: High-load roller bearings and dual-lip seals to prevent leakage.
Working Principle:
1. Suction Phase: Pistons retract, increasing cylinder bore volume. Hydraulic oil enters through the valve plate inlet.
2. Discharge Phase: Pistons extend, reducing cylinder bore volume. High-pressure oil exits through the valve plate outlet.
3. Variable Control: Adjusts swashplate angle to modify piston effective stroke, altering displacement.
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5. Applications
• Construction Machinery:
• Excavator hydraulic systems (main pump or travel pump).
• Crane luffing/slewing mechanisms.
• Road roller vibration systems.
• Industrial Equipment:
• Injection molding machine hydraulic drives.
• Metal die-casting machine clamping systems.
• CNC machine tool hydraulic clamping.
• Marine and Offshore Engineering:
• Deck machinery (anchors, winches).
• Steering gear hydraulic systems.
• Specialized Fields:
• Simulation test benches (e.g., flight simulators).
• Hydraulic presses (high-precision forming).
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6. Common Faults and Solutions
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Fault Symptom Possible Causes Solutions
Insufficient Flow Clogged suction filter, small swashplate angle, internal leakage Clean filter, adjust variable mechanism, replace seals
Pressure Fluctuation Worn valve plate, oil contamination, air ingestion Repair valve plate, replace hydraulic oil, bleed air
Abnormal Noise Bearing failure, piston seizure, cavitation Replace bearings, clean piston pairs, check suction lines
High Oil Temperature Inadequate cooling, excessive displacement, improper oil viscosity Enhance cooling, adjust displacement, use correct oil
Severe Leakage Aged seals, excessive gap between cylinder block and valve plate Replace seals, lap valve plate surface
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7. Selection and Procurement Guide
Selection Steps:
1. Determine System Requirements:
• Maximum operating pressure (≥28 MPa).
• Required flow rate (calculate based on actuator demands).
• Speed range (match motor/engine specifications).
2. Variable Control Selection:
• Manual: Low cost, suitable for fixed operations.
• Hydraulic: Fast response, suitable for remote control.
• Electronic: High precision, suitable for automated systems.
3. Port Matching:
• Confirm inlet/outlet sizes (e.g., G3/4, G1).
• Check mounting orientation (vertical/horizontal).
4. Environmental Adaptability:
• High-temperature environments: Select high-temperature seals.
• Corrosive environments: Stainless steel options.
Procurement Recommendations:
• Prefer original manufacturers or authorized distributors (e.g., Rexroth, Parker, Kawasaki equivalent products).
• RequestCE certification,performance test reports, andwarranty documents.
• Spare parts inventory: Seal kits, valve plates, bearings.
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8. Maintenance and Upkeep
Daily Inspections:
• Oil cleanliness (NAS 6 grade or better).
• Interface tightness (no leaks).
• Abnormal noise or vibration.
Scheduled Maintenance:
• Every 500 hours: Replace suction filters.
• Every 2000 hours: Replace hydraulic oil (recommend 46# anti-wear hydraulic oil).
• Every 5000 hours: Inspect valve plate and cylinder block clearance; repair if necessary.
Long-Term Storage:
• Drain oil and fill with rust-preventive oil.
• Coat piston bores with grease to prevent corrosion.
