The universal joint cross-shaft needle bearing of the drive shaft should be lubricated with gear oil. However, it is generally found in automobile maintenance that the universal joint cross-shaft needle bearing of the transmission shaft is lubricated with calcium-based grease (commonly known as butter). Actually, this lubrication method is wrong, resulting in a large number of cross-shaft needle bearings. Early damage. In the disassembly, it can be clearly seen that the cross shaft journal presents a groove that is squeezed and pressed, and the journal and the needle are severely deficient in oil.
Why would such phenomenon happen? Because the lubricating oil nozzle of the universal joint cross-shaft needle roller bearing is an ordinary grease fitting, it gives people an illusion that it has been generally lubricated with grease for a long time. In fact, it is difficult to fill the butter bearing to the needle bearing with a grease gun from the nozzle.
As we all know, the viscosity of butter is large. When a grease gun is used to fill the inner cavity of the universal joint cross-shaft needle bearing with a grease gun, the resistance of the butter enters the narrow inner oil passage, and the pressure of the butter rises. The pressure reducing valve overflows.
This phenomenon is also mistaken by drivers and repairers for having been filled with butter. In fact, the butter does not enter the needle between the needles at all, and it is very difficult to reach the end of the cross shaft journal. When the maintenance is removed, the grease can be applied to the needle roller and journal surface by a forced method. However, for the lubrication effect of the cross-shaft needle roller bearing, the calcium-based grease is far less than the gear oil. Ok, the reason is:
a. The universal joint is subjected to a large torque and alternating load during work, and the oil film of the calcium-based grease is tough, and it is difficult to form a good oil film on the friction surface of the bearing and the journal.
b. The needle roller bearing of the universal joint cross shaft can only rotate in place during the work, can not rotate along the steel bowl and the cross journal, and the calcium-based grease has poor rolling property, so it cannot be formed immediately after the oil film is destroyed. New oil film.
c. Calcium-based grease is a mixture of oil and calcium soap. In use, due to the deterioration and evaporation of lubricating oil, the grease becomes a harder calcium soap. The calcium soap itself can not only play a lubricating role. Moreover, it also hinders the rolling of the needle on the journal, and there is no oil draining measure in the universal joint cross shaft. The deteriorated grease can neither be discharged, and the new oil is difficult to inject, thus greatly accelerating Wear of the needle roller bearing of the pitch shaft.
In order to change the wrong way of lubricating the universal joint cross-shaft needle bearing with butter instead of gear oil, the following maintenance methods are recommended to improve the service life of the universal joint cross-shaft needle bearing.
a. Remove the universal joint cross shaft needle roller bearing and thoroughly clean it. Remove all residual grease (can be boiled or put into gasoline for cleaning), then put it in gear oil for 2min~l0min, then it can be used. . In use, it should be noted that the new oil should be replaced in time after the car is wading. New oil should be replaced once between 2000km and 3500km. This method has been tested to extend the life of universal joint cross-shaft needle bearings by a factor of two to three.
b. It can be equipped with special hydraulic filling equipment to regularly lubricate the universal joint cross-shaft needle bearing of the transmission shaft.
Aerospace&Ground Support Casters
Aerospace&Ground Support Casters
Aerospace&Ground Support Casters
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