Choice of Lubricating Oil For Cross Universal Joint

Cross universal joint manufacturer have to withstand large torsion and alternating loads during work. The maintenance industry used to use calcium-based grease to lubricate the cross shaft. However, due to the poor toughness of the oil film of calcium-based grease, it is difficult to form a good oil film on the friction surface between the bearing and the journal, which is the cause of the early damage of the universal joint cross shaft needle roller bearing.

In addition, due to the design structure of the old universal joint cross shaft, when the repairman uses a grease gun to add grease to the inner cavity of the cross shaft through the grease nozzle, because the viscosity of the grease is high, the resistance to enter the narrow inner oil groove is very large. At this time, the grease will overflow by pushing the pressure reducing valve on the opposite side of the oil nipple. This makes the repairman mistakenly believe that the bearing has been filled with grease. In fact, in many cases, the grease cannot enter between the needle rollers and reach the end face of the cross journal. It is also more difficult.

Therefore, the maintenance industry uses gear oil instead of grease to lubricate the universal joint cross shaft. It is said that after comparative experiments, the service life of lubricating the universal ten-byte with gear oil is 2 to 3 times that of lubricating with ordinary butter. However, this also requires special pressurized oiling tools, and the cross shaft needs to be removed for cleaning during the first refueling, which is more troublesome. In addition, the retention of gear oil is not as good as grease, and its lubrication cycle needs to be shortened.

Therefore, more and more people choose to use extreme pressure lithium complex grease for the lubrication of universal joints. First, the fluidity is better, so that it is easy to reach the lubrication part. Second, the grease has good extreme pressure resistance and is suitable for universal ten-byte working conditions. According to our understanding of users, the current development trend of universal joint cross shafts is to eliminate oil filling holes, so grease with the same life span of precision universal joint as the equipment components must be selected.