At the friction points between the crankshaft and the bearings, the crosshead and the slide plate, the packing and the piston rod, etc., the temperature exceeding the specified value is called overheating. The consequences of overheating: one is to accelerate the wear between the friction pairs, and the other is that the heat of the overheating continues to accumulate until the friction surface is burned and the lock is burned, causing major machine accidents. The main causes of bearing overheating are: uneven fit between the bearing and the journal or too small contact area; deflection of the bearing, bending and twisting of the crankshaft; too low viscosity of the lubricating oil, blockage of the oil circuit, failure of the oil pump, etc.; during installation There is no leveling, no clearance is found, the main shaft and motor shaft are not aligned, the two axes are tilted, etc.