The importance of NSK bearing grease stability

In general, the amount of grease in the NSK bearing always exceeds the actual amount required to directly participate in the lubrication, in the cavity of the holder and the bearing cover, and forms a contour on the periphery of the rolling element. During this process, the bearing temperature rises rapidly due to the resistance of the excess grease. Although most of the excess grease is squeezed out at the beginning of the run, the grease that is squeezed into the raceway attachment may still be carried by the rolling element into the raceway. In the early stages of the bearing, most of the grease is squeezed out of the raceway very quickly (less than a minute), and the build-up grease is discharged a small amount while circulating along with the bearing rotor. At this time, the bearing temperature continues to rise until the excess bearing grease is completely discharged, which can be called the walking phase of the grease. According to the grease quality and filling amount in the bearing structure, this time may last for more than ten. Minutes, even hours.
After the remaining bearing grease is completely discharged, the remaining small amount of grease forms a thin layer of grease film on the mutual contact surface of the rolling element, the raceway and the cage, thereby entering the normal stage of the bearing. . At this time, the temperature gradually drops and reaches equilibrium. In other words, long-term lubrication is mainly borne by this layer of grease film. In addition, during the long-term operation of the bearing, the contour of the rolling element and the raceway and the grease on the cage are shrunk to separate a part of the base oil, and after flowing into the raceway, the lubrication is also supplemented. .
Different bearing greases are not the same in the contours of the bearings. It is necessary to form a contour that is relatively straightforward. The running time is short. In the long-term operation, the bearing temperature is low and stable. This is an ideal one. Grease is especially important for grease channeling.
Some so-called eddy-flow greases are not easy to form contours, and even if they are contoured, they are easy to collapse. At this time, the excess grease repeatedly returned to the raceway is in a state of being strongly stirred for a long time, and the bearing torque is large and the temperature is high. Unbalanced, noise may also be generated, and grease is also prone to deterioration and loss.
NSK bearing temperature rise treatment
When the bearing temperature rises, first judge whether it is malfunctioning. If it does rise, it should be treated as follows:
(1). Check the cooling water pressure, water flow and piping system is normal. If the water pressure is low, the filter may be clogged and cannot be disposed of in time. It can be shut down and put into use when it is confirmed that it can work.
(2). Check the oil pressure of the governor. If the oil pressure is low, the cooling water hydraulic valve may be closed.
(3). Check if the bearing has abnormal sound, NSK bearing and check if the bearing swing is abnormal.
(4). Take oil samples to see if there is any change in oil color.

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