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Effect of Vibration and Temperature on INA Bearing Damage
Nov 28, 2018

When INA bearings work, the loads on the rollers and inner rings (or outer rings) are not constant, but change with the running cycle of the bearings. This kind of load is alternating load, and because the contact area between rolling body and inner ring (or outer ring) is very small, the contact stress is very large. At higher speed, under the repeated action of the huge alternating contact stress, the metal will be fatigued. Initially, micro-cracks can be seen in the stress concentration area. Because of the effect of lubricant and corrosion of metal, the cracks gradually expand. When the cracks expand to a certain extent, the surface metal will spall and form small impression pits, similar to pits. When we dismantle and inspect bearings, we often find inner or outer rings and the surface of rolling bodies. There are pits and pieces of metal peeling, which is the phenomenon of metal fatigue peeling.

Fatigue spalling of INA bearings should be regarded as natural damage if it occurs after a long period of operation. If it occurs in the middle or early period of service, it should be regarded as non-natural spalling. At this time, the cause of spalling should be identified.

The main causes of unnatural spalling are improper selection of bearing type or improper installation.

(1) Early peeling may occur when deep groove ball bearings are selected under large axial loads due to improper selection of bearing types. Peeling mainly occurs in the raceway, which makes the rolling track of the rolling element move towards the ball loading orifice, even roll over the ball loading orifice, and finally causes serious peeling damage to the raceway. The measure to prevent this kind of damage is to select the bearings reasonably according to the working conditions of the bearings.

In the use of INA bearings, it can be said that vibration and temperature have a great impact on the bearing. Let's first look at the impact of bearing vibration on INA bearings.

Vibration is very sensitive to bearing damage. Peeling, indentation, rust, crack and wear can be reflected in bearing vibration measurement. Therefore, the size of vibration can be measured by using special bearing vibration measuring device (frequency analyzer, etc.), and the specific situation of abnormality can not be inferred by frequency. The measured values vary with the use conditions of bearings or the installation position of sensors, so it is necessary to analyze and compare the measured values of each machine before determining the judgment criteria.

Let's look at the effect of temperature on bearings.

High temperature is often used to indicate that INA bearings are in abnormal condition. High temperature is also harmful to the lubricant of bearings. Sometimes the overheating of bearings can be attributed to the lubricant of bearings. If the temperature of the bearing exceeds 125 C for a long time, the service life of the bearing will be reduced. Causes of high temperature bearing include: insufficient or excessive lubrication, lubricant. It contains impurities, excessive load, bearing ring damage, insufficient clearance, and high friction caused by oil seal, etc.

Therefore, continuous monitoring of bearing temperature is necessary, whether it is to measure the bearing itself or other important parts. If the operating conditions are unchanged, any temperature change can indicate that a fault has occurred.

Periodic measurements of bearing temperature can be made by means of thermometers, such as digital thermometers, which can accurately measure the temperature of INA bearings and display them in units of C or Fahrenheit temperature. Important bearing means that when it is damaged, it will cause equipment shutdown, so it is better to install temperature detectors for such bearings.