Vibration and temperature of bearings

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Vibration and temperature of bearings 1. Bearing vibration Bearing vibration has a significant impact on the integrity of bearings; issues such as flaking, indentation, rusting, cracks, and wear can all be detected through vibration measurements of bearings. Therefore, by using specialized devices for measuring bearing vibration (such as frequency analyzers), it is possible to determine the level of vibration, and frequency analysis can help identify the specific nature of any abnormalities. The measured values vary depending on the operating conditions of the bearings or the installation location of the sensors, etc.; therefore, it is necessary to analyze and compare the measurement values for each machine in advance in order to establish judgment criteria. 2. Bearing temperature The bearing’s temperature can generally be estimated from the temperature outside the bearing housing; it would be more appropriate if the temperature of the outer ring of the bearing could be measured directly through the oil holes. 　　Typically, the temperature of the bearing gradually rises as it starts to operate, and reaches a stable level after 1-2 hours. The normal temperature of a bearing varies depending on the machine’s heat capacity, heat dissipation rate, speed, and load. If the lubrication and mounting are inadequate, the bearing temperature will rise sharply, resulting in abnormally high temperatures; in such cases, operation must be stopped and necessary preventive measures taken. 　　By using a thermal sensor, it is possible to monitor the operating temperature of the bearing at any time, and to trigger an automatic alarm or stop the operation when the temperature exceeds the specified value, thereby preventing bearing burnout accidents. 　　High temperatures often indicate that the bearing is in an abnormal condition. High temperatures are also harmful to the lubricant in bearings. Sometimes bearing overheating can be attributed to the bearing’s lubricant. If the bearing operates continuously at temperatures above 125°C, its lifespan will be reduced. The causes of high-temperature bearings include: insufficient or excessive lubrication, and the lubricant itself. It can be caused by impurities, excessive load, damaged bearing rings, insufficient clearance, and high friction generated by the oil seal, among other things. 　　Therefore, it is necessary to continuously monitor the bearing temperature, whether by measuring the bearing itself or other important components. If the operating conditions remain unchanged, any change in temperature indicates a fault has occurred. 　　Regular measurement of bearing temperature can be carried out using thermometers, such as SKF digital thermometers, which allow for accurate determination of the bearing temperature and display it in degrees Celsius or Fahrenheit. 　　Bearings of critical importance mean that their failure can cause the equipment to stop operating; therefore, it is advisable to equip such bearings with temperature sensors. Under normal conditions, bearings experience a natural temperature rise immediately after lubrication or re-lubrication, and this rise persists for one or two days.