1.Force fit

The Bearing inner ring of the high-speed machine tool is tightly matched with the shaft, and when the outer ring is loosely fitted with the bearing seat hole, a Force fit can be used to press the bearing on the shaft first, and then install the shaft together with the bearing into the bearing seat hole. When assembling, on the end face of the inner ring of the bearing, an assembly sleeve (copper or mild steel) made of a soft metal material is placed. The inner diameter of the assembly sleeve should be slightly larger than the diameter of the journal and the outer diameter should be slightly larger than the flange of the inner ring of the bearing Small, so as not to press on the cage.

When the outer ring of the bearing is tightly fitted with the hole of the bearing seat ,but the inner ring is loosely fitted with the shaft, the bearing can be pressed into the hole of the bearing seat firstly. And the outer diameter of the assembly sleeve should be slightly smaller than the diameter of the seat hole. If the bearing ring and the shaft and the seat hole are tightly matched, the installation of the inner ring and the outer ring must be pressed into the shaft and the seat hole at the same time. The structure of the assembly sleeve should be able to press the end surfaces of the bearing inner ring and the outer ring at the same time.

2Heating coordination

By heating the bearing or bearing housing, the thermal expansion is used to transform the tight fit into a loose fit installation method. It is a common and labor-saving installation method. This method is suitable for the installation of spindle bearings of high-speed machine tools with a large interference. Before the hot assembly, the bearing or the separable bearing ring is placed in the oil tank and heated evenly at 80-100 ℃. On the top, in order to prevent the end face of the inner ring and the shaft shoulder from being tight after cooling, the bearing can be axially tightened after cooling.

When the outer ring of the bearing is tightly fitted with the bearing seat made of light metal, the hot fitting method of heating the bearing seat can be used to prevent the mating surface from being scratched. When heating the bearing with an oil tank, there should be a grid at a certain distance from the bottom of the tank, or hang the bearing with a hook. The high-speed machine tool spindle bearing cannot be placed on the bottom of the tank to prevent sinking impurities from entering the bearing or uneven heating. With a thermometer, the oil temperature must be strictly controlled not to exceed 100 ° C to prevent the tempering effect and reduce the hardness of the ferrule.