Universal joints are subjected to a large torque and alternating load during work. However, due to the poor toughness of the oil film of the calcium-based grease, it is difficult to form a good oil film on the friction surface of the bearing and the journal, so actually this type of lubricant is not recommended.
In addition, due to the design of the old-fashioned universal joint cross shaft, when grease is added to the inner cavity of the cross shaft through the grease nozzle, due to the large viscosity of the grease, the resistance to enter the oil passage of the narrow inner oil groove is big, the pressure will overflow from the pressure relief valve opposite the nozzle, which causes the repairman to mistake the bearing for full greasing. In fact, there are many cases where the grease can not only enter between the needles or the end of the cross journal.
It is said that after comparison experiments, the service life of the universal joint with gear oil is 2 to 3 times that of ordinary butter. However, there is also a need for a special pressurized oiling tool, and the cross shaft should be removed for cleaning during the first refueling. Also, the gear oil is not as retentive as grease, and its lubrication cycle needs to be shortened.
Considering the above reasons, the 2# extreme pressure lithium complex grease is used to lubricate the universal joint, and its fluidity is good, it can reach all internal parts easily; and the grease has good extreme pressure resistance and is suitable for universal working status. According to our understanding of users, the current development trend of universal joints is to cancel the oil hole. Therefore, the grease with the same life as the equipment parts must be selected.www.morayshaft.com