1bearingOverheating core warning signal
temperature threshold
If the temperature of the outer ring of the bearing exceeds 80 ℃ (which needs to be monitored in real time by an infrared thermometer), or is 10 ℃~15 ℃ higher than the normal operating temperature and continues to rise, the machine should be stopped immediately for inspection.
Abnormal noise and vibration
High frequency screaming or irregular knocking sounds may be accompanied by pitting corrosion on the bearing raceway; If the vibration value of the equipment exceeds the ISO 10816 standard (such as the effective value of the grinding machine vibration speed>4.5mm/s), it indicates that the bearing is in an abnormal working state.
Signs of lubrication failure
If the lubricating grease becomes thin, leaks, or has a burnt smell, it indicates that the lubrication system has failed and requires emergency treatment.
2、 Three step temperature reduction method for emergency response
Immediate shutdown and risk isolation
Press the emergency stop button to cut off the power supply and avoid bearing jamming or bearing melting caused by high temperature.
If it is the main bearing of the mill, turn on the auxiliary motor to slowly rotate the equipment (such as in the case of a ball mill) to prevent damage to the oil film between the hollow shaft and the lining tile.
Quick cooling operation
Forced air cooling: Use compressed air or a fan to blow towards the bearing seat to accelerate heat dissipation (avoid directly blowing the seal).
Temporary cooling device: If conditions permit, wrap the bearing seat with ice packs or coolant (for short-term emergencies only, long-term improvement of the cooling system is required).
Root cause investigation and repair
Lubrication system inspection:
Confirm whether the amount of lubricating grease added is within the range of 1/2~2/3 of the bearing chamber volume. Excessive amount will cause stirring and heating, while insufficient amount will result in insufficient lubrication.
Check if the lubrication pipeline is blocked (such as testing the oil supply pressure with a pressure gauge), clean or replace the filter.
Take an oil sample for analysis. If the lubricating grease deteriorates (such as acid value exceeding the standard or cone penetration change>30%), thoroughly clean the bearing housing and replace it with new grease.
Cooling system optimization:
Check the cooling water flow rate (which should be ≥ 80% of the design value) and return water temperature (which should be 5 ℃~10 ℃ lower than the inlet oil temperature), and clean the cooler scaling (such as acid washing scaling).
If the cooling effect is insufficient, a new cooler can be installed in parallel or the area of the heat sink can be increased.
Mechanical troubleshooting:
Check the installation tolerance of the bearing: the interference fit between the inner ring and the shaft should be within the range of 0.01~0.03mm, and the gap between the outer ring and the end cover should be ≤ 0.05mm.
Measure bearing clearance: The radial clearance should meet the design value (such as retaining a clearance of 0.05~0.1mm for roller bearings). If the clearance is too small, it will cause oil shear heating, and if it is too large, it will cause rotor movement.
Coupling alignment: Use a laser centering device to adjust, ensuring that the axial deviation between the motor and the bearing seat is ≤ 0.05mm and the angle deviation is ≤ 0.05 °/m.
3、 Long term cooling strategy and preventive measures
Lubrication management upgrade
Choose high-temperature lubricating grease (such as NLGI No.3 lithium grease) with a drip point ≥ 250 ℃, which can meet the continuous operation requirements of the polishing machine.
Implement timed and quantitative lubrication: replenish oil every 50 hours, and the amount of oil added each time is calculated based on the bearing chamber volume and filling coefficient (e.g. 6204 bearings require approximately 15g).
Cooling system renovation
For high load conditions (such as stone polishing machines), using a circulating oil cooling jacket for cooling can increase the heat dissipation efficiency by more than three times compared to natural cooling.
Add a cooling water flow control valve to automatically control the flow rate based on the bearing temperature (such as fully open when the temperature is greater than 70 ℃).
Standardization of equipment maintenance
Establish a bearing temperature monitoring file, record the daily highest temperature and its trend, and provide early warning of potential faults.
Develop a "Bearing Replacement Cycle Table": classify according to working conditions (such as 8000 hours of light load and 4000 hours of heavy load) to avoid exceeding the service life.
4、 Typical cases and data support
Case 1: The bearings of a polishing machine in a certain stone factory frequently overheat. By replacing the lubricating grease with high-temperature synthetic oil (base oil viscosity index>150) and adding a forced air cooling device, the bearing life was extended from 3 months to 1 year.
Case 2: The temperature of the main bearing of a ball mill in a metal processing plant was too high. After inspection, it was found that the cooler had scaled, resulting in a 40% decrease in heat transfer efficiency. After acid cleaning and descaling, the temperature returned to normal, saving an annual maintenance cost of 120000 yuan.
Data: According to statistics, 40% of bearing failures are caused by poor lubrication, 25% are caused by insufficient cooling, and 15% are related to installation errors (source: SKF Bearing Failure Analysis Report).