Analysis of Abnormal Phenomenon Caused by FAG Bearings

One: FAG bearing grease rheology:

1. When the grease is not subjected to external force, it can maintain a certain shape like a solid, that is, it will not automatically lose when it is at rest.

2. In the case of extremely high shear stress (high shear rate), the grease flows like a Newtonian fluid, and the viscosity can be kept constant without changing with the shear rate.

3. When subjected to weak external force, elastic deformation occurs; after removing the external force, it can return to its original position and shape, exhibiting the elastic properties of the solid.

4. When the applied external force is large enough, the grease deforms and flows, and thus can no longer automatically return to the original position and shape, so the starting torque of the grease on the mechanically moving part is larger than that of the liquid lubricating oil.

Two: FAG bearing grease defects:

1. Grease is semi-solid and does not flow at normal temperature, so it is difficult to add grease or change grease on friction parts. FAG bearing cleaning is not very convenient.

2. The stirring resistance is large, so the heat generation is large and the cooling effect is poor. However, it should be noted here that this has a close relationship with the lubrication method. If the lubricating oil is lubricated with a fully immersed (or semi-immersed) oil bath, the grease will consume less power than the oil. For example, the British Journal of Friction and Lubrication reported in 1973, 6th issue: With a rolling FAG bearing with a diameter of 100, the speed is 1500r/min, and it is lubricated with grease. There are many examples of energy consumption in China, such as the refractory plant of Chongqing Iron and Steel Company. The motor power of the refractory tunnel kiln induced draft fan is grease compared to the N68 lubricant. The FAG bearing temperature is 4~6 °C lower.

3. The base oil is the carrier of the additive, and the additive does not function if the base oil fails.

4. Due to the mechanical action, the lubricating base filled in the FAG bearing configuration will gradually lose its lubricating properties. Therefore, the grease needs to be continuously replenished and updated. The interval between lubricant replenishment varies depending on the formation, size, and rotational speed of the FAG bearing, and the approximate interval of replenishment of the grease is required depending on the operation time.

For more information and purchase please visit: https://www.supplyforever.com

Process characteristics for judging the vibration of imported bearings and the temperature of imported bearings

First, the vibration of imported bearings

The vibration of the imported bearing is very sensitive to the damage of the imported bearing. For example, peeling, indentation, rust, crack, wear, etc. will be reflected in the vibration measurement of the imported bearing. Therefore, by using a special bearing vibration measuring device (frequency analyzer, etc.) The magnitude of the vibration is measured, and the specific situation of the abnormality cannot be inferred by the frequency division. The measured values ​​vary depending on the conditions of use of the bearing or the mounting position of the sensor. Therefore, it is necessary to analyze and compare the measured values ​​of each machine in advance to determine the judgment standard.

Second, the temperature of the imported bearings

The temperature of the imported bearing is generally estimated by the temperature outside the bearing. If the oil hole can directly measure the temperature of the outer ring of the imported bearing, it is more suitable.

Usually, the temperature of the imported bearing rises slowly as the bearing starts to run, and reaches a steady state after 1-2 hours. The normal temperature of the imported bearings varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubrication and installation parts are suitable, the temperature of the imported bearings will rise sharply, and abnormal high temperature will occur. At this time, it is necessary to stop the operation and take necessary precautions.

The thermal sensor can be used to monitor the working temperature of the imported bearing at any time, and automatically alarm or stop the occurrence of the burning shaft accident when the temperature exceeds the specified value.

The use of high temperatures often indicates that the bearing is in an abnormal condition. High temperatures are also detrimental to the lubricants of imported bearings. Sometimes bearing overheating can be attributed to the lubricant of the bearing. Long-term continuous rotation of the bearing at temperatures above 125 °C will reduce bearing life. Causes of high temperature imported bearings include: insufficient lubrication or excessive lubrication, lubricants. Containing impurities, excessive load, loss of imported bearings, insufficient clearance, and high friction caused by oil seals.

Therefore, it is necessary to continuously monitor the temperature of the imported bearings, whether it is measuring the bearing itself or other important parts. If the operating conditions are the same, any temperature change can indicate that a fault has occurred.

The periodic measurement of the temperature of the imported bearing can be carried out by means of a thermometer, such as a digital thermometer, which can accurately measure the temperature of the imported bearing and display it in °C or Fahrenheit.

For more information and purchase please visit: https://www.supplyforever.com