Checking the condition of the machines in operation and preparing a thorough inspection plan has become more and more serious. Among them, the bearing is the focus of attention, because it is the most important rotating part in all machines. Condition monitoring is an important part of preventive maintenance. Early detection of bearing damage to avoid equipment downtime during unplanned maintenance due to bearing damage. However, not all of them are equipped with this advanced instrument. In this case, the operator or maintenance engineer of the machine must be highly alert to the "fault signals" of the bearing, such as noise, temperature and vibration. "Listening", "touching" and "observing" are three important factors. The views provided below can be used as your reference.
High temperature often indicates that the bearing is in abnormal condition. High temperatures are also harmful to the lubricants in SKF bearings. Sometimes bearing overheating can be attributed to the lubricant of the bearing. Long-term operation of the bearing at a temperature exceeding 125 degrees Celsius will reduce the life of the bearing. The reasons for the high temperature of the bearing include: insufficient or excessive lubrication, impurities in the lubricant, and excessive load , Bearing damage, insufficient clearance, and high temperature friction caused by oil seals, etc. Therefore, continuous monitoring of bearing temperature is necessary, whether it is measuring the bearing itself or other important parts. If the operating conditions do not change, any temperature change may indicate that a malfunction has occurred.
The bearing temperature can be measured regularly with the help of a thermometer, which can accurately measure the bearing temperature and display it in degrees Celsius. The important bearing means that when it is damaged, it will cause the shutdown of the equipment, so it is best to install a temperature detector for this type of bearing. Under normal circumstances, the bearing will have a natural temperature rise just after lubrication or relubrication and it will last for one or two days.
Click here for more information about SKF 3210 A-2ZTN9/MT99.
1. Selection of bearing model: The bearing model is generally selected by the user's technical personnel according to the use conditions and load bearing of the supporting products. The business personnel mainly know whether the actual load of the user is consistent with the selected bearing. If the bearing does not meet the requirements for use, the customer should be advised to change the model as soon as possible, but unless there is a special product in the selection of the model, there will generally be no problems.
2. Selection of bearing clearance: When purchasing a bearing, users generally only inform about the model and grade, and rarely ask for the clearance of the bearing. The business person must ask about the bearing's operating conditions, the speed and temperature of the bearing. , Fitting tolerances are directly related to the choice of bearing clearance. Generally, motors with speeds below 3500 rpm mostly use CM clearance, such as high-temperature and high-speed motors that require relatively large clearances. After assembly, the bearing clearance will be reduced due to the expansion of the inner hole and the shrinking of the outer circle. The reduction of the clearance = the interference amount × 60% (except the bearing chamber is aluminum). For example, the clearance before assembly of the bearing is 0.01mm, and the interference during assembly is 0.01mm, then the clearance after assembly of the bearing is 0.004mm. In theory, the noise and life of the bearing reach the best state when there is zero clearance, but in actual operation, considering the temperature rise and other issues, the clearance of the bearing after assembly is preferably 0.002mm-0.004mm.
3. The choice of grease: The choice of grease is generally based on the speed, temperature resistance, noise requirements and starting torque of SKF bearings. The business personnel are required to have a good understanding of the performance of various greases.
4. Selection of bearing seal type: bearing lubrication can be divided into oil lubrication and grease lubrication. Oil-lubricated bearings are generally selected in the form of bearings, and grease-lubricated bearings are generally sealed with dust caps or rubber seals. The dust cover is suitable for high temperature or good use environment. The seals are divided into contact seal and non-contact seal. Contact seal has good dust resistance but large starting torque, and non-connected seal has small starting torque but sealing performance. No contact is good.
SKF bearings are currently professionally manufactured in industries such as automotive motor bearings, home appliance motor bearings, motorcycle bearings, and health-care motor bearings, so that the noise and life of the bearings are at their best.