Generally speaking, the needle roller bearing of universal joint cross axle of transmission shaft should be lubricated with gear oil, but in practice, it is often directly replaced by calcium-based grease, which many users disagree with. But in fact, this kind of lubrication is wrong, and the early damage of needle roller bearings is also related to this aspect.

In the process of disassembling bearings, it can be seen that the cross shaft journal has presented a groove of squeezed medium pressure, indicating that the oil shortage at the journal and needle roller has been quite serious. At this time, if the right choice of lubricants, and the right addition, the problem will soon be solved.

But the type of lubricating oil used at the beginning has been wrong, and it is difficult to add butter to needle roller bearings with butter gun. Because of the high viscosity of butter, when butter is injected from the nozzle to the inner cavity of universal joint cross needle roller bearings, the resistance of butter entering the narrow inner chamber increases, and the pressure of butter rises to top the pressure relief valve opposite the opening nozzle and spills out.

But the user will not think that this is wrong, but it is regarded as a sign that the needle roller bearings have been filled with lubricant, but in fact, butter has not entered the needle, even to reach the end of the cross shaft journal is very difficult.

In disassembly and maintenance, even if butter is applied on needle roller and journal surface by forced method, it can also play a role in lubrication, but for the lubrication effect of cross-axle needle roller bearings, calcium-based grease is far inferior to gear oil, so it is recommended that we use gear oil to lubricate needle roller bearings.

In this way, the normal operation of needle roller bearings can be ensured, and the phenomenon of early damage can be avoided. At the same time, the whole transmission shaft can maintain a good state in work and play its due role.