Created on:2022-02-18 13:03

Troubleshooting and maintenance of gear hydraulic motor

Troubleshooting and maintenance of gear hydraulic motor

1. Common faults and troubleshooting of gear motor

1. The hydraulic motor has obvious noise and vibration, accompanied by heating

(1) Causes.

1) Poor meshing of gears. When the gear motor is worn or foreign matters enter, the tooth profile accuracy of the hydraulic motor decreases or the meshing contact is poor.

2) The hydraulic motor bearing or bearing seat is damaged. When the bearing or bearing seat of the hydraulic motor is damaged, the support of the shaft cannot be guaranteed, and shaking or vibration and noise will occur during operation.

3) The axial clearance of hydraulic motor does not meet the requirements. When the axial clearance of the hydraulic motor is too small, there will be obvious noise and vibration during operation, accompanied by heating.

4) The inner hole of the gear of the hydraulic motor is not perpendicular to the end face, or the two holes on the front and rear end covers of the hydraulic motor are not parallel.

5) The viscosity of hydraulic oil does not meet the requirements. When the viscosity of the hydraulic oil used is too high or too low, noise will be generated.

6) The oil filter is blocked by dirt.

7) Air enters the hydraulic system. When the pump inlet pipe joint leaks; When there is oil leakage somewhere in the hydraulic system; When a part of the hydraulic system is poorly connected, it will cause the system to enter the air. When the hydraulic oil with a large amount of air enters the hydraulic motor, it will produce vibration and noise.

8) The tank level is too low.

9) The aging of hydraulic oil and poor defoaming performance cause air bubbles to enter the hydraulic motor.

(2) Methods of exclusion.

1) The way of tooth deformation can also be used to reduce the noise when replacing the gear or studying and finishing the gear.

2) Replace the damaged bearing or bearing seat, etc.

3) Grind the side plate or gear end face to increase the axial clearance, but the axial clearance shall not be greater than the technical requirements.

4) Replace unqualified products.

5) Replace the hydraulic oil with proper viscosity.

6) Clean the oil filter to reduce the pollution of hydraulic oil.

7) The system shall be comprehensively inspected, the pump inlet pipe joint shall be tightened, and the seal damaged shall be replaced.

8) Add hydraulic oil to the specified level of the oil tank.

9) If the hydraulic oil is seriously polluted and aged, it shall be replaced.

2. If the speed of the hydraulic motor fails to reach the specified speed, the output torque also decreases

(1) Causes.

1) The oil supply of the hydraulic pump is insufficient. The hydraulic pump in the hydraulic system fails to work normally, and the output flow of the hydraulic pump decreases; The speed of the hydraulic pump is not enough, which is mainly due to the mismatch between the speed and power of the motor driving the hydraulic pump, resulting in insufficient output flow and insufficient flow and pressure into the hydraulic motor.

2) The performance of hydraulic oil does not meet the requirements. Generally, the hydraulic oil viscosity is too small, resulting in increased leakage in various parts of the hydraulic system.

3) There is a problem with the control valve in the hydraulic system. For example, when the pressure regulating valve (e.g. overflow valve) of the hydraulic system fails to regulate, the pressure does not go up, and the leakage in each control is large, resulting in insufficient flow and pressure into the hydraulic motor; When the opening of the flow control valve is adjusted too small, the flow of hydraulic oil into the hydraulic motor is too small.

4) Hydraulic motor itself. For example, the side plate and gear sides of CM hydraulic motor are worn and pulled, resulting in large internal leakage between high and low pressure chambers and even string chambers; Because there is no gap compensation, the rotor and stator are sealed in line contact, and the sealing line in the whole hydraulic motor is long, which leads to leakage and low efficiency. Especially when the contact line between rotor and stator is damaged due to poor tooth profile accuracy or strain, the leakage is more serious, resulting in the decrease of speed and output torque.

5) System overload. When the working load is large, the hydraulic motor is unable to work, resulting in reduced speed.

6) Other components of the hydraulic system are faulty.

(2) Methods of exclusion.

1) Eliminate the problem of insufficient oil supply of hydraulic pump. Check the reason why the hydraulic pump cannot work normally. If the fit clearance increases due to wear, repair or replace the corresponding parts in time, and check whether the motor meets the requirements. If it does not meet the requirements, replace the motor that can meet the requirements of revolution and power.

2) Check the viscosity of hydraulic oil and replace the hydraulic oil with appropriate viscosity in time.

3) Check and eliminate the faults of each control valve. The key point is to check the overflow valve and flow valve, check the cause of pressure regulation failure and whether the opening of flow valve is appropriate, and take targeted measures to eliminate their faults.

4) Grind and repair both sides of the side plate and gear of the hydraulic motor, and ensure the assembly clearance, that is, the hydraulic motor body should also be ground out of the corresponding size.

5) Check the cause of excessive load and eliminate it.

6) Check one by one and take corresponding measures.

3. The oil seal of hydraulic motor leaks oil

(1) Causes.

1) There is a problem with the installation or selection of drain pipe. Due to improper installation of the oil drain pipe, the pressure of the oil drain pipe will be high, resulting in oil leakage of the oil seal.

2) The journal is strained due to poor oil seal quality or damaged oil seal.

(2) Methods of exclusion.

1) The oil drain pipe is connected to the oil tank separately instead of sharing the oil return pipeline of the hydraulic motor; Clean the drain pipe and remove the blockage; If the diameter of the drain pipe is too small or bent, the drain pipe with larger diameter shall be replaced to minimize or avoid bending.

2) Replace the high-quality oil seal or replace the damaged oil seal; Grind and repair the shaft to avoid being pulled again.

2. Maintenance of gear hydraulic motor

The repair method of main parts of gear hydraulic motor is basically the same as that of gear pump, which can be referred to.

3. Precautions for use of gear hydraulic motor

(1) There are many structural forms of gear hydraulic motor. The selected hydraulic motor should first meet the requirements of load and speed, and then comprehensively consider the indicators and conditions of the selected hydraulic motor, such as starting performance, low-speed stability, efficiency, noise, reliability, economy, convenience of use and maintenance, timeliness of delivery and so on. Priority should be given to products that have been identified and technologically mature by relevant national departments and industries.

(2) The back pressure at the oil drain port of gear hydraulic motor shall not be greater than 0.05Mpa.

(3) The working medium of gear hydraulic motor is recommended to use 46 hydraulic oil or other kinematic viscosity (25 ~ 33) × Neutral mineral oil of l0-6m2 / S (at 50 ℃).

(4) The output shaft of gear hydraulic motor and the actuator shall be installed with elastic coupling, and the coaxiality error shall not be greater than 0.1mm. The coaxiality error of shaft sleeve coupling shall not be greater than 0.05mm.

(5) Before installing the gear hydraulic motor, check whether the rotation direction of the gear hydraulic motor is consistent with the direction indicated by the product.

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