Causes of damage of Timken thrust needle roller bearing and its maintenance skills
Causes of damage of Timken thrust needle roller bearing and its maintenance skills
2022年3月23日
Necessity of Selecting lubricant for Bearing Maintenance
Necessity of Selecting lubricant for Bearing Maintenance
2022年3月24日

Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

  • Many factors in real life affect the bearing, such as temperature, vibration, etc. These are the factors that affect the needle roller bearing. How can we prevent the impact of these factors on NTN bearing? The following mainly introduces the impact of vibration and temperature on the bearing:

Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

1、 Bearing vibration

  • NTN bearing is sensitive to vibration damage, such as peeling, indentation, corrosion, crack, wear, etc., which will be reflected in the bearing vibration measurement. Therefore, the vibration is measured by special needle roller bearing vibration meter (frequency analyzer, etc.), and the frequency point cannot be inferred through unusual conditions. 
  • The measured value is due to the use of sensor bearing or?? The conditions of the installation position are different, so it is necessary to compare the standards determined by the analysis and measured values of each machine in advance.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

2、 Bearing temperature

  • NTN bearing temperature can be inferred from the temperature outside the general bearing chamber. If the temperature of the outer ring of the bearing can be measured directly, it is more appropriate.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease
  • Usually, the temperature of needle roller bearing starts to rise slowly and runs for 1-2 hours to reach a stable state. For the heat capacity of the machine, normal temperature bearing, refrigeration capacity, speed and load change.
  •  If lubricating and installing the corresponding parts, NTN bearing will have a sudden temperature rise, and there will be abnormally high temperature. When the operation is stopped, take necessary preventive measures.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease
  • The temperature sensor can monitor the working temperature of NTN bearing at any time, and realize that the temperature exceeds the specified value, so as to prevent automatic alarm or stop combustion shaft accident.

Is the viscosity of the bearing grease

  • NTN bearing grease is usually expressed by apparent viscosity or similar viscosity. When describing the viscosity of grease, the temperature and shear speed must be indicated. Similar viscosity indexes can be used to control its low-temperature fluidity and pumpability.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

The second is the low temperature fluidity of bearing grease

  • One of the important indicators to measure the low-temperature performance of NTN bearing grease is the low-temperature torque, that is, the degree to which the grease blocks the rotation of low-speed flow needle roller bearing at low temperature (- below 20 ° C).
  •  The Low-Temperature Torque of grease is expressed by the average value of starting torque and torque after rotating for 60mm.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease
Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

The third is the evaporation of bearing grease

  • The evaporation (degree) of NTN bearing grease indicates the degree of volatilization of grease oil when the grease is used for a long time under high temperature conditions. The smaller the evaporation, the better. The evaporation of grease mainly depends on the properties and fraction composition of lubricating oil.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease
  • The fourth is the oxidation stability of bearing grease
  • Oxidation stability refers to the ability of lubricating grease to resist the action of heat and oxygen and keep its properties from permanent change when it is stored for a long time or used at high temperature for a long time. 
  • Due to oxidation, the content of free alkali is often reduced or the content of free organic acid is increased, the dropping point is reduced, the appearance color is darker, there is a strange odor, the consistency, strength limit and similar viscosity are reduced, and corrosive products and substances that destroy the structure of lubricating grease are generated, resulting in the separation of soap and oil. 
  • Therefore, in the long-term storage of lubricating grease, it should be stored in a dry and ventilated environment to prevent sunlight exposure, and the changes of free alkali or free organic acid, corrosivity and other items should be checked regularly to ensure its quality and performance.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease

The fifth is the thixotropy of bearing grease

  • The basic characteristic of NTN bearing grease is thixotropy. When an external force is applied, the flow of grease gradually softens and the viscosity decreases, but once it is at rest, the consistency increases (recovers) again after a period of time (very short). This characteristic is called thixotropy. 
  • This characteristic of grease determines that it can be lubricated in parts that are not suitable for lubricating oil lubrication, and shows its excellent performance.Reduce the influence of vibration and temperature on NTN needle roller bearing through rational use of lubricating grease
Technical requirements for Timken non-standard bearing