The relationship between the cleanliness of NSK bearings and heat

In the popular situation, the filling amount of nsk bearing grease always surpasses the practical requirement of direct intervention lubrication, saturating the cavity on the frame and the bearing cover of the rolling mill, and forming a contour on the periphery of the rolling element. During this process, the bearing temperature rises rapidly due to the resistance of 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 transferred to change the rolling element into the raceway.
In the initial stage of the rolling mill bearing operation, most of the grease is squeezed out of the raceway very quickly (less than one minute), and accumulated in the grease retaining body following the transfer of the bearing transfer body, and is discharged a small amount. At this time, the temperature of the nsk bearing continues to rise until the excess grease is completely discharged. It can be called the running phase of the grease. According to the quality of the grease in the bearing structure of the rolling mill, the filling amount, etc., this time may last for more than a dozen. Minutes, even hours.
a, the impact on the life of NSK bearings:
The cleanliness of NSK bearings has a considerable impact on bearing life. Bearing companies have conducted special tests for this purpose, and the result is several times or even dozens of times. The higher the cleanliness of the bearing, the longer the life and the like. The test shows that the lubricating oil with different cleanliness has a great influence on the life of the ball bearing. Therefore, improving the cleanliness of the lubricating oil can prolong the life of the rolling mill bearing. In addition, if the lubricating oil-containing dirt particles are controlled below 10 um, the bearing life is also increased several times.
b. Impact on vibration and noise:
Impact on vibration: The NSK bearing test results show that the cleanliness seriously affects the vibration level of the rolling mill bearings, especially in the high frequency band. Bearings with high cleanliness have low vibration speed values, especially in the high frequency band.
c. Impact on lubrication performance:
The decrease in the cleanliness of the NSK bearing not only affects the formation of the lubricating oil film, but also causes deterioration of the grease and accelerates its aging, thereby affecting the lubricating performance of the grease.

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Timken thrust needle roller bearing damage reasons and maintenance skills

Before the thrust needle roller bearing is completely destroyed, it provides sufficient time for the user to find out. Do not ignore the existence of such friction. It will slow down the riding speed and make the long-distance physical power consumption more slower. If the roughness of the surface is small, if the lubricating film has a proper thickness, the probability of surface stress generation is relatively low, which is why it is necessary to properly select the appropriate oil for lubrication. However, if the pressure load exceeds The pu value of the oil film (fatigue load limit value, such as excessive speed, excessive pressure impact), the fatigue of the material will come sooner or later.
In order to let the timken bearing clamp the axis, the friction phenomenon of the bushing is prevented (this phenomenon will generate high temperature instantaneously on the high-speed rotating machine, causing the lubricating oil to burn out and even cause the heat to rise and become stuck), so the inside of the bearing The 铛 and the outer bowl (also known as the bearing box in the industry) use a kind of "overweight" phenomenon. Generally speaking, the shaft is larger than the inner sill, or the outer bowl is larger than the load. This kind of interference requires a lot of power to install. Into, and such loading requires a great force to strike the Palin, which will cause the Palin to be damaged during the tapping process, so the industrial large timken bearings usually adopt heating, hydraulic jacking and the like.
(1) The degree of difficulty in forming an alloy by metallurgical materials.
(2) Affinity of materials and lubricants.
(3) The friction factor of the auxiliary material in the non-lubricated state.
(4) The microstructure of the material.
(5) Thermal conductivity of the material.
(6) The size of the surface energy of the material and the characteristics of the oxide film.
The high-pressure oil is injected into the timken bearing through the nozzle by the oil pump, and the oil injected into the thrust needle roller bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at a high speed, the rolling elements and the cage also form a gas flow at the relatively high rotation speed of the surrounding air. It is difficult to send the lubricating oil to the thrust needle roller bearing by the general lubrication method, and the high pressure injection method must be used. Lubricating oil is sprayed into the double row deep groove ball bearings. The position of the nozzle should be between the inner ring and the center of the cage.

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