Removal method of forklift hitting fault:
The cpcd5aiiz forklift has a strong impact and abnormal noise when the gear is in use. Because the car is equipped with hydraulic shift fixed shaft variable speed reducer or differential is caused by loose.
The drive shaft of the main reducer turned its input shaft by hand and found that there was nearly 30 degrees of free rotation clearance, so it was judged that the tooth reduction clearance of the main reducer was too large. Remove the main reducer and measure the gap to 0.65mm (standard value is 0.30-0.50mm). Adjust the position of the bevel teeth so that the tooth gap with the driving bevel gear is 0.35mm. After re-assembling and testing the machine, the gear is still impacted by the gear and emits abnormal noise, the degree is only slightly reduced than the original, but the fault remains.
To this end, remove the drive shaft again, leaving the transmission in a no-load state. Start the engine and repeat the gear shift, push gear, and gear shift tests. It is found that the abnormal noise that is generated at the moment of gear shift still exists, and the transmission has obvious vibration. Check that the supporting bolts of the transmission are not loose. Judging from this phenomenon, the fault should be inside the transmission. Disassemble, clean and inspect the transmission, and found that the tapered roller bearings of the main and driven shafts of the reverse and forward clutches are loose. Adjust the bearing to the proper clearance by adding or removing spacers, and reassemble the test machine. The impact of the gear impact and the occurrence of abnormal noises have been reduced, but the failure phenomenon still exists.
After such a detailed inspection, the root cause of the failure has not been found, so is there any defect in the design or manufacture of this type of forklift? Therefore, the forklifts of the same model produced by the factory were found for road tests of gear shifting, pushing gear, and lifting gear. It was found that there was a slight impact of gear shift, but the severity was different. Therefore, the focus of the search for the cause of the fault should be on the hydraulic control part of the transmission. Consult the transmission control diagram and parts catalog of the machine to know that the piston return of the clutch is achieved by the preload of the spring. Therefore, at the moment of gear shift, there may be a situation where the pressure control oil flow is too large, so the spring preload is quickly overcome, so that the driving disc and the driven disc are engaged too fast to produce the same gear shock. In order to verify this idea, it is necessary to make some modifications to its hydraulic control pipeline. An adjustable flow valve is connected in series between the directional valve and each clutch piston to control its flow rate so that it can achieve the purpose of smooth engagement.
