Created on:2021-05-12 09:03

Common faults of hydraulic motor and general methods of diagnosis and elimination

Common faults of hydraulic motor and general methods of diagnosis and elimination


Fault phenomenon

Cause analysis

Exclusion method

A. Low speed and low torque

1. Insufficient oil supply of hydraulic pump

(1) Insufficient prime mover speed

(2) The filter screen of oil suction filter is blocked

(3) It is difficult to absorb oil due to insufficient oil in the oil tank or too small suction pipe diameter

(4) The seal is not tight, there is leakage, and the air invades the interior

(5) The viscosity of the oil is too high

(6) The axial and radial clearance of hydraulic pump is too large, and the internal leakage increases

(7) Variable mechanism failure

(1) Find out the reason and adjust it

(2) Clean or replace the filter element

(3) Add enough oil and increase the pipe diameter properly to make the oil absorption unobstructed

(4) Tighten the joints to prevent leakage or air intrusion

(5) Choose oil with low viscosity

(6) Proper repair of hydraulic pump

(7) Maintenance or replacement

2. The output oil pressure of hydraulic pump is insufficient

(1) The efficiency of hydraulic pump is too low

(2) The adjustment pressure of relief valve is too low or there is a fault

(3) Excessive tubing resistance (too long or too thin pipe)

(4) The viscosity of the oil is small and the internal leakage is large

(1) Check and eliminate the malfunction of hydraulic pump

(2) Check the fault of relief valve and increase the pressure again after troubleshooting

(3) Replace the pipe with larger diameter or reduce the length as much as possible

(4) Check the sealing condition of the internal leakage part and replace the oil or seal

3. Hydraulic motor leakage

(1) The joint surface of hydraulic motor is not tightened or the seal is not good, resulting in leakage

(2) The internal parts of hydraulic motor are worn and leaking seriously

(1) Screw the joint surface to check the sealing condition or replace the sealing ring

(2) Check the damaged parts and repair or replace the parts

4. The hydraulic motor is damaged

The supporting spring of valve plate is fatigued and out of action

Check and replace the support spring

B. The speed is too high

Excessive oil supply

(1) Hydraulic pump prime mover speed too high

(2) The flow setting value of variable displacement pump is too large

(3) The flow area of the flow valve is too large

(4) Beyond the role of load

(1) Replacement or adjustment




C. 泄露大

1. 内部泄露











2. 外部泄露









D. 噪声大




















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