Common failures of forklift hydraulic mechanical drive train
The common faults of the hydraulic mechanical transmission system of the internal combustion forklift are: insufficient output power, difficulty in starting, slow shift response; excessive oil temperature and hydraulic torque converter not working.
Failure analysis
If it is found that the forklift has insufficient power, difficult climbing, slow shift response, and the load lifting work is normal, first use a pressure gauge to check the system pressure. If the specified pressure value is not reached, the reason may be: Excessive wear of gears and pump body causes excessive wear of the gears and pump body of the compensation pump, which increases leakage in the compensation pump; poor cleanliness of the oil causes clogging of the oil circuit and causes the compensation to suck in.
If the oil temperature is too high, the usual reason is: the oil supply is insufficient due to the blockage of the compensation pump, causing the clutch to dry friction and causing the oil temperature to be too high; the oil pressure in the torque converter is lower than the adjustment pressure of the main pressure valve, so that The outlet pressure of the torque converter is too low; the oil grade is incorrect; the internal components of the torque converter are damaged, so that only a small part of the engine power is transferred to the turbine, and the reactive power is too large, causing the oil temperature to rise sharply.
If the torque converter does not work from the observation hole of the torque converter, you should first check the oil inlet and return conditions of the torque converter. If there is no oil return, and the forklift is cold and the car is running normally and the car is hot If the driving is difficult, the cause of the failure is to compensate the serious wear or damage of the pump; if the torque converter has no power output and sometimes does not work during operation, the cause of the failure is clogged oil path, damaged inner sleeve of the guide wheel seat, or loose nut of the guide wheel seat.
Troubleshooting
From the above analysis, it can be seen that the faults of the forklift hydraulic mechanical transmission system are mainly three links: oil circuit, hydraulic torque converter and compensation pump. Therefore, when troubleshooting, you should first consider cleaning the oil circuit, replacing the oil and oil filter as required; then check the three links of the torque converter and the compensation pump. Therefore, when troubleshooting, you should first consider cleaning the oil circuit and replace the oil and oil filter as required; then check whether the guide wheel, guide wheel seat and overrunning clutch of the torque converter are damaged; finally check the compensation pump for wear , And repair or replace damaged components. The dust and dirt on the surface of the oil radiator must also be cleaned. After the above-mentioned treatments are carried out, the faults can be generally eliminated.
When overhauling the special dynamic system, attention should be paid to the following inspections and adjustments; the coaxiality error of the engine flywheel, torque converter and torque converter shell should not be greater than 0.2mm; the dynamic imbalance of the connecting disc should be less than 30g·cm; the engine flywheel The end runout of the end face of the shell and the end face of the torque converter relative to its axis is not more than 50UM; there should be a gap of 1.0-1.5mm between the torque converter fork and the end face of the compensation pump gear.
