Fault diagnosis for the movement and vibration of vibratory rollers

1. Check whether there are mechanical faults in the connection components between the engine and the hydraulic pump, as well as between the hydraulic motor and the drive wheels; Check whether the bypass valve installed on the front drive motor is in the open path state.

2. Check the braking system. When the engine is operating normally and the solenoid valve is energized, see if the brake can be disengaged. If it cannot be disengaged, check for mechanical faults. If not, you can use the dragging method to release the brake (turn the manual pump handle counterclockwise), and then proceed with the following checks.

3. Check the high-pressure pressure and oil replenishment pressure of the main circuit of the walking hydraulic system. Connect 60 mpa oil pressure gauges to each of the two high-pressure pressure measurement ports, and 4mpa oil pressure gauges to the oil replenishment pressure measurement port, and then conduct a test run. At normal temperatures (30 to 60℃), the oil replenishment pressure is approximately 26 mpa, and it should not be less than 24mpa when the machine is in operation. When encountering resistance during walking, the maximum pressure of the main circuit can reach 38 mpa, and it should not be less than 20 mpa during normal walking. If both are normal, it indicates that the fault lies in the mechanical aspect.

If the oil replenishment pressure is lower than the specified value, place the walking control lever in the middle position to adjust the overflow valve of the oil replenishment pump (Note: Observe the oil replenishment pressure gauge during adjustment. The adjustment range should not be too large and remember the original position). If the pressure cannot reach the normal value or the pressure gauge reading remains unchanged, it can be determined that there is a fault with the overflow valve or the oil replenishment pump. If the oil replenishment pressure is normal when the machine is not running, but drops significantly during the walking operation, the pressure of the return oil pipe on the walking motor should be measured. This pressure should not be less than 2 mpa. If the pressure is low, it indicates that there is a fault with the shuttle valve and the low-pressure relief valve of the motor. When the oil replenishment pressure is higher than the specified value, the pressure of the relief valve can be reduced. If it cannot be reduced, it indicates that there is a fault with the relief valve.

If the high-pressure pressure is low, the fault may be caused by the hydraulic pump, hydraulic motor, or multi-functional valve block (including the high-pressure relief valve). The two main pipes of the pump can be removed, and the outlet of the pump can be blocked with a plug. Let the engine idle and slowly push the walking rod forward and backward at a small Angle. If the pressure is abnormal, the multi-functional valve block should be disassembled and inspected. If the multi-functional valve is normal, it is caused by internal leakage of the hydraulic pump. If the high pressure is normal, it indicates that there is a problem with the motor. To determine which motor is faulty or if both motors are faulty, you can respectively remove the inlet and return oil pipes of the front and rear motors, block them with plugs, and then test the machine. The motor whose pressure is still abnormal is the faulty motor. It can also be determined by measuring the oil leakage of the motor. The method is to disassemble the oil leakage pipe of the motor and connect a measuring cylinder. A leakage of 3 to 4 l/min under normal pressure is normal; otherwise, it indicates that there is a fault with the motor.

Diagnosis of Vibration System Faults

After eliminating electrical faults, check the condition of the elastic coupling between the vibration motor and the vibration shaft as well as the lubricating oil inside the vibration shaft. Excessive lubricating oil can prevent the vibration frequency from rising. This is usually caused by the damage of the oil seal in the motor assembly and oil leakage inside the shaft. If the spline sleeve of the vibration shaft is severely worn

2. As the front and rear vibration systems of the machine are both independent and interrelated (sharing the same make-up oil pump), the "component replacement method" can be applied for diagnosis. For instance, when the vibration frequency of one round is low, the pipelines of the front and rear motors can be swapped. If the fault has been transferred, it indicates that the fault lies in the pump; otherwise, it is a motor fault. Similarly, the same "interchangeability method" can also be adopted for diagnosis of displacement control valves used in variable frequency operations.