How to properly maintain the cross bearing of the universal joint

Update:11-08-2020
Summary:

In addition to good anti-friction and anti-wear propert […]

In addition to good anti-friction and anti-wear properties, the requirements for lubricating materials for automobile transmission shaft cross bearings should also have good mechanical stability, high temperature (high dropping point), corrosion resistance, water resistance and oxidation stability. And other characteristics.
The high temperature and water resistance of gear oil cannot meet the requirements. In addition to calcium-based grease (hereinafter referred to as calcium-based grease), there are also lithium-based grease (hereinafter referred to as lithium-based grease), aluminum-based grease, and sodium-based grease. In fact, No. 2 or No. 3 lithium-based grease has always been used for the lubrication of automobile drive trains, because lithium-based grease has a higher dropping point than calcium-based grease (lithium-based grease is 170℃-190℃, calcium-based grease It is 90℃-100℃) and good thermal stability.


The technical requirements for disassembling cross needle roller bearings are relatively high. Generally, it is necessary to go to an auto repair shop to be completed by a professional repairer. The lubrication of the cross shaft of the drive shaft is a routine maintenance item. Generally, maintenance is required every 2000km. If every maintenance is to the repair shop, this will undoubtedly increase the economic burden of the owner; if each vehicle is equipped with a dedicated Hydraulic filling equipment is also unrealistic. With grease lubrication, only an ordinary grease gun is needed for the driver to complete, which is time-saving and economical.
However, the incorrect operation method of some drivers may cause the grease to not enter the bearing. The correct operation method is: press the oil outlet of the grease gun firmly on the grease nipple, and continuously operate the grease gun to make the grease enter the internal oil passage of the cross shaft through the grease nipple under pressure, and then reach the 4 journals of the cross shaft The end face is filled with needle roller bearings, and at the same time, the degraded grease and impurities remaining in the needle roller bearings are squeezed out from the oil seal. After the deteriorated grease and impurities in each bearing are all squeezed out (seeing that fresh grease is squeezed out), the operation is completed. If the grease cannot be pressed into the bearing during operation, replace the grease nipple or remove the cross shaft to clean the oil passage, and then refill it to ensure driving safety.
In addition, with the continuous development of the automotive industry, molybdenum disulfide grease has been widely used in the automotive industry. The so-called molybdenum disulfide grease is made by adding a small amount of colloidal aluminum disulfide to lithium-based grease or complex calcium-based grease. Molybdenum disulfide is a flake crystal, and its sulfur atom has a strong affinity for metal, so it is easy to form a firm lubricating oil film on the friction surface.

 

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