Yuken vane pump noise problem solution

1. Pre-Maintenance Safety Preparation & Tool Preparation

1.1 Safety Operation Specifications (Mandatory)

• Shut down and relieve pressure: Immediately stop the operation of the vane pump, cut off the corresponding power supply, and hang a “Under Maintenance, No Switching On” sign. Let the system stand for more than 30 minutes to release residual pressure, and manually rotate the shaft 3 times to confirm that the pressure is completely relieved to prevent high-pressure oil splashing and injury.
• Environmental protection: Clean up debris in the maintenance area to keep it ventilated and dry, avoiding dust and impurities from entering the pump body. Operators should wear non-slip gloves and protective glasses to prevent contact with high-temperature oil or sharp components.
• Oil handling: Drain part of the oil in the hydraulic system in advance (keep the minimum liquid level to prevent dust from entering the pipeline), store it in a clean container, and decide whether to reuse it after testing the oil condition.

1.2 Necessary Tools & Accessories

• Basic tools: Torque wrench (with M16 adapter), hexagon wrench, screwdriver, puller, seal disassembly tool, pipe wrench.
• Testing tools: Sound level meter, pressure gauge, vibration sensor (optional), oil cleanliness tester (NAS grade), vernier caliper.
• Spare parts: Yuken original seals, bearings (matching the corresponding pump model), filter elements, hydraulic oil (ISO VG46 anti-wear hydraulic oil is recommended), coupling elastic elements, shock-absorbing pads (Shore hardness 50~60).

2. Noise Type Judgment & Preliminary Troubleshooting

3. Targeted Solutions for Common Faults

3.1 Excessive Noise Caused by Cavitation (Most Common Fault)

Solution Steps:

1. Troubleshoot air leakage points: Disassemble the suction pipeline interfaces (flanges, joints), check whether the sealing gasket (thickness ≥3mm) is aged or damaged, and replace it with Yuken original seals. Apply soapy water to the interface, start the pump for no-load operation, and observe if there are bubbles. If so, re-tighten the interface bolts (M16 bolt torque ≥180N·m).
2. Handle suction obstacles: Replace the suction filter (use Yuken original filter element), clean the suction pipeline, and remove impurities and scale in the pipeline. Check the oil tank vent, and clean the blockage with compressed air or a clean cloth to ensure pressure balance inside and outside the oil tank.
3. Adjust oil condition: Add hydraulic oil to the standard liquid level (more than 50mm above the suction port) to avoid vortex suction. If there are too many bubbles in the oil, start the pump for no-load operation for 10~15 minutes, open the system air release valve to discharge air, and check the position of the return pipe to ensure that the return pipe port is inserted below the oil level to avoid air being brought in by the return oil.
4. Optimize suction conditions: If the suction vacuum is too high (>0.03MPa), adjust the pump installation height, shorten the suction pipeline length, and avoid excessively long suction pipeline and too many elbows. If necessary, add a pre-inflation device to reduce suction resistance.

3.2 Excessive Noise Caused by Mechanical Wear

Solution Steps (Taking Yuken PV2R Series Vane Pump as an Example, Other Series Can Be Referenced):

1. Pump disassembly: Disassemble in the order of “end cover → main shaft → valve plate → rotor → vane → stator”, and mark the components (to avoid assembly dislocation). Handle with care during disassembly, wipe the surface of components with a clean cloth to avoid scratches and collisions, and do not knock precision components with brute force.
2. Component inspection and replacement:
   1. Bearings: Measure the bearing clearance (standard range 0.01~0.05mm). If the clearance exceeds the standard, the ball surface is worn, or the cage is broken, replace it with Yuken original bearings of the same model, and apply special grease before installation.
   2. Vanades and rotor: Check whether the vanes are stuck or worn, clean impurities in the pump body, adjust the fit clearance between vanes and stator, and replace damaged vanes or stator to ensure that the fit clearance of the moving pair meets the design requirements.
   3. Valve plate: Check whether the end face has scratches or ablation (sealing belt damage), measure the flatness (≤0.005mm). If it exceeds the standard, perform precision grinding or replace it in pairs to ensure that the contact surface with the rotor is >85%.
3. Pump assembly: Assemble in the reverse order of disassembly. Apply clean hydraulic oil to the vanes before installing them into the rotor, align the positioning pin of the valve plate with the shell hole, and tighten the bolts step by step according to the torque (to prevent eccentric load deformation). After assembly, manually rotate the shaft to ensure flexible rotation, no jamming, and no abnormal noise.

3.3 Excessive Noise Caused by Installation Deviation

Solution Steps:

1. Coupling correction: Disassemble the coupling, check whether the elastic elements are aged or cracked, and replace them with original elastic elements. Adjust the coaxiality of the pump body and the motor to ensure radial runout ≤0.1mm and axial runout ≤0.05mm. Reinstall the coupling and tighten the bolts, and manually rotate the shaft to confirm no eccentricity or jamming.
2. Pump installation adjustment: Check whether the anchor bolts of the pump body are loose and tighten them according to the original torque standard. Replace the aging and deformed shock-absorbing pads (Shore hardness 50~60) to ensure stable installation of the pump body and avoid severe vibration during operation. If the installation surface is uneven, add adjustment gaskets to ensure horizontal installation of the pump body.
3. Pipeline optimization: Check the fixation of the hydraulic pipeline, add pipe clamp fixation (especially for long pipelines and elbows) to avoid pipeline loosening. Optimize the pipeline layout, reduce the number of elbows, replace pipelines with mismatched diameters (avoid excessive fluid pulsation caused by too small diameters), and reduce the risk of pipeline resonance. In the hydraulic station of power machinery, a flexible joint can be added at the interface between the pipeline and the pump body to absorb vibration.

3.4 Excessive Noise Caused by Oil Quality or System Matching

Solution Steps:

1. Oil quality improvement: Drain the contaminated hydraulic oil completely, clean the oil tank and pipeline thoroughly, and inject Yuken recommended hydraulic oil (ISO VG46 anti-wear hydraulic oil is preferred). Regularly detect the oil cleanliness (maintain NAS grade ≤8) and replace the filter element every 2000~3000 operating hours.
2. System parameter adjustment: Check the system pressure and flow, adjust the relief valve and flow valve to ensure that the operating parameters of the pump are within the rated range. Avoid long-term operation of the pump at the maximum pressure or maximum speed, which can reduce noise and component wear.
3. Eliminate trapped oil noise: For variable vane pumps, check whether the valve plate has triangular grooves in the oil sealing area. If not, add triangular grooves to prevent pressure surges caused by trapped oil and eliminate trapped oil noise.

4. Preventive Maintenance Measures

• Regular inspection: Check the pump body temperature, vibration, and noise every day during operation; check the oil level, oil color, and filter pressure difference every week; conduct a comprehensive inspection of the pump and hydraulic system every month, including seal condition, coupling alignment, and pipeline fixation.
• Regular oil change: Replace the hydraulic oil every 6 months or 5000 operating hours (whichever comes first), and clean the oil tank and filter during oil change to avoid oil contamination.
• Component replacement: Replace vulnerable parts (seals, filter elements, coupling elastic elements) regularly according to the service life specified in the Yuken manual; replace worn vanes, bearings, and valve plates in time to avoid fault expansion.
• Installation optimization: When installing or reinstalling the pump, ensure the coaxiality of the pump and motor, use qualified shock-absorbing pads, and optimize the pipeline layout to avoid pipeline resonance. Keep the maintenance area clean to prevent impurities from entering the pump body.
• Operational standardization: Avoid frequent start-stop and overload operation of the pump; preheat the hydraulic system for 5~10 minutes before starting the pump in low-temperature environments to ensure that the oil viscosity meets the operating requirements.

5. Summary