Why is the kitchen exhaust fan squeaking all the time?

Provide several possible reasons and methods, please compare them yourself: 1. It is too dirty, and the dirt rubs against each other, so remove the dirt; 2. The rotating blades are too dirty, which makes the rotor unbalanced when rotating, and the inner and outer shells of the bearing room rub against each other to remove oil pollution; 3. After the bearing rotates for a long time, it is a little short of oil, and the bearings rub against each other. Please drop a small amount of lubricating oil. 4. The bearing is worn and needs to be replaced; I don't know which screw is loose. When the fan rotates, there is friction between the whole and the fixed seat. Just tighten it.