Unplug the cord. The base and fan are generally fixed with three screws. Use a screwdriver of appropriate size to unscrew them. After removing the fan, you can see a trademark sticker on the back of the fan. If you tear off the sticker, you can see the main shaft of the fan. Apply lubricating oil (preferably low-density lubricating oil), then stick it on, and then reattach it according to the removal process. When applying oil, rotate the fan from time to time to allow the oil to completely enter the fan shaft