Troubleshooting of Hydraulic Motor

Figure 1: Hydraulic motor.

1. Disassembly Procedure

1.1 Preparation before disassembly

1. Remove the oil drain plug and drain the oil in the motor housing.
2. Loosen the five screws on the oil pan and remove the oil pan.
3. Take out the oil distribution plate, locating ring, cushion block, cylindrical pin and double headed key.

Figure 2: Structure of a hydraulic motor.

1.2 Disassembly Sequence

1. Remove the cover, screw in the central screw hole with clean screws, and lift out the crankshaft.
2. Remove the snap ring on the connecting rod.
3. Take out the assembly of the connecting rod of the plunger body, and make corresponding marks one by one, so that the original clearance can still be guaranteed during reassembly. Generally, users can check and repair it here. If necessary, they can disassemble the assembly of the plunger body and connecting rod: loosen the spring retaining ring for the hole, take out the retaining ring, and the plunger body and connecting rod can be separated.
4. Assemble according to the reverse procedure above, and pay attention to ensure the axial clearance of the bearing.
5. All parts must be cleaned before assembly to prevent scratching or bumping any working surface.
6. If only the sand hole of the plunger sleeve leaks oil or the joint surface between the plunger sleeve and the housing leaks oil, please loosen the screw on the plunger sleeve, remove the plunger sleeve, and replace the plunger sleeve or "O" ring.

2. Common Faults and Troubleshooting

Figure 3: Hydraulic motor troubleshooting.

2.1 The Rotation is Opposite to the Predetermined Direction

Cause: the oil distribution plate is installed reversely.

Solution: Remove the oil distribution plate, take out the oil distribution plate, rotate it 180 degrees and reinstall it.

2.2 Serious External Leakage of Motor

Solution:

1. Check the contact surface between the oil pan and the housing.
2.Check the seals connected between the parts.
3.Check the viscosity and working oil temperature of the hydraulic oil.
4. Wear of the parts of the moving pair.

2.3 Large Leakage in the Motor

Solution:

1. Check the wear of the sealing ring on the oil distribution plate.
2. Check the wear of the oil pan and whether the two oil chamber channels at the oil inlet and outlet of the casting are connected.

2.4 The Motor does not Rotate and the Pressure does not Go up

Cause:

1. Other parts of the system are faulty.
2. The double headed key is broken.
Solution:

1. Check the system and eliminate it.
2. Remove the oil pan and oil distribution pan and replace the parts.

2.5 The Motor does not Turn and the Pressure Increases

Cause:

1. A moving pair inside the motor bites each other.
2. The load exceeds the set value.
Solution:

Disassemble for inspection and replace parts.

Figure 4: Keep all parts of the motor clean.

2.6 Other Oil Leaks at the Contact Surface with the Housing

Cause: the rubber sealing ring is damaged or aging.

Solution: Replace the rubber sealing ring.

2.7 Abnormal Noise

Cause: 1. The connecting rod and the bearing sleeve are bitten or damaged. 2. The snap ring is broken and the bearing is bitten. 3. The coupling is not concentric 4. External vibration 5. Noise of other hydraulic systems.

Solution: 1. Replace the parts, check the bearing on the thrust seat for damage and clearance, and correct it. 2. Check the coaxiality of the coupling connected to the motor and correct it. 3. Correct the coaxiality 4. Take shockproof measures 5. Check the system and eliminate faults.

2.8 The Temperature Rises too Fast

Cause: 1. insufficient cooling of the system. 2. Major parts are seriously worn.

Solution: The same as the troubleshooting method in fault 4.

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