Created on:2021-05-26 16:06

Trouble shooting of axial piston pump

Trouble shooting of axial piston pump

Taking the axial piston pump widely used in China as an example, the following table introduces some common faults and troubleshooting methods of the axial piston pump in use.


Some common faults and troubleshooting of axial piston pump


Fault phenomenon

Cause analysis

Exclusion method

Pump cannot build up pressure or insufficient flow

(1) Click reverse connection of steering or installation error of solenoid directional valve

(1) Exchange or correction

(2) Too much oil is discharged from the leakage pipe

(2) Unscrewing the oil drain pipe and judging by visual inspection, if the oil is ejected, it means that the efficiency is reduced

(3) Water or oil mixed impurities in the oil

(3) The water in the oil is milky white, the inferior oil is soy sauce or black tar, change the oil

(4) A filter screen is installed on the oil inlet or the filter screen is blocked

(4) Select the filter screen with larger mesh or remove it

(5) Air leakage or crack on oil inlet pipe

(5) Apply grease to check. If the sound is reduced, it indicates that the pipeline is leaking. Replace the seal or pipeline

(6) There is not enough oil in the tank

(6) Fill up according to the requirement of oil tank

(7) Improper size of pipe, valve or pipe joint

(7) Improvement after measurement according to the instruction

(8) Too long oil inlet pipe and too many elbows

(8) The length of oil inlet pipe shall be less than 2.5m and the number of elbows shall not exceed 2

(9) The coaxiality of pump and prime mover is out of tolerance

(9) After parking, the coupling should be easy to handle and have axial clearance, otherwise, the coaxiality should be adjusted to eliminate interference

(10) Improper setting pressure of relief valve or excessive leakage in valve and actuator

(10) If the leakage in the cylinder is too large, the piston rod will crawl

(11) Start up before opening the oil inlet valve

(11) The pump is worn and needs to be repaired

(12) The electromagnetic directional valve does not change direction

(12) Exchange

(13) Oil viscosity too high or oil temperature too low

(13) Change the oil with lower viscosity or heat the oil tank

(14) There is something wrong with the electrical part

(14) Handled by relevant personnel

(15) The copper layer of the cylinder block falls off or the bearings are damaged, or the plunger slippers are burned

(15) Check and replace

(16) There is dirt between the valve plate and the pump body, or the positioning pin of the valve plate is not installed properly, so that the valve plate and the cylinder body do not fit well

(16) Disassemble the pump, clean the moving parts and reassemble

(17) The deflection angle of the variable mechanism is too small, so that the flow is too small, the relief valve can not establish pressure or is not adjusted properly

(17) Increase the deflection angle of the variable mechanism to increase the flow, check whether the damping hole of the relief valve is blocked and whether the pilot valve is sealed, and readjust the relief valve

(18) The leakage of other components in the system is too large

(18) Replacement of relevant components

(19) The pressure compensation variable displacement pump can not reach the pressure required by the hydraulic system

① The variable mechanism is not adjusted to the required power characteristic

② When the temperature rises, the required pressure is not reached

(19) Check and adjust

① Readjust the variable characteristics of the pump

② Reduce the system temperature or replace the components with excessive leakage due to temperature rise

External leakage

(1) Aging of sealing ring

(1) Remove and inspect the sealing part, check the damaged part of O-ring phase skeleton oil seal and the scratch, bump, burr, etc. of the matching part in detail, and grind it clean, and replace with a new sealing ring

(2) Leakage at oil seal of shaft end framework

① Wear of framework oil seal

② Wear of transmission shaft

③ The oil pressure in the low pressure chamber exceeds 0.05Mpa. The frame seal is damaged

④ The diameter of external drain pipe is too small or the pipe is too long

(2) Disassembly and inspection

① Replace the framework oil seal

② Slight wear can be corrected with metallographic sandpaper and oilstone, and serious eccentric wear should be returned to the manufacturer for replacement

③ Clean the oil drain port, repair two pairs of moving oil, replace the framework oil seal, use special tools during assembly, and the lip should be toward the pressure oil side to ensure the sealing

④ Replace the proper drain pipe

Excessive vibration and noise

(1) Pump not filled or not filled

(1) Refuel

(2) The pump has been running at low pressure

(2) Exhaust air after high pressure operation for 5 ~ 10min

(3) The viscosity of the oil is too high, and the oil temperature is lower than the allowable working temperature range

(3) Change the oil suitable for the working temperature or warm up the engine at low speed before starting

(4) Water in the oil or mixed with impurities (poor oil is black)

(4) Change the fluid

(5) The resistance of oil absorption channel is too large, the filter screen is partially blocked, the pipeline is too long, and there are too many elbows

(5) Reduce the resistance of oil suction passage

(6) Air leakage in oil suction pipe

(6) Apply grease to the joint to check and eliminate air leakage

(7) Air leakage of hydraulic system (return pipe is not inserted below the liquid level)

(7) Insert all return pipes 200 mm below the oil level

(8) Pump and prime mover coaxiality difference, or shaft interference and coupling loose vibration

(8) Re adjust the coaxiality (no more than + 0.05mm) I. after parking, the manual coupling should be easy to handle

(9) The oil in the oil tank is insufficient or the oil drain pipe is not inserted below the liquid level

(9) Increase the oil in the oil tank to make the liquid level within the specified range, and insert the drain pipe below the liquid level

(10) Piping not in accordance with recommended pipe, valve or pipe joint size

(10) Pipe according to the recommended pipe or pipe joint size

(11) The air vent or air filter in the oil tank is blocked

(11) Clean the air vent or air filter on the oil tank

(12) System pipeline vibration

(12) Set pipe clamp to reduce vibration























Home    Article    Trouble shooting of axial piston pump