we usually call ball bearings because it belongs to deep groove ball bearings, rolling steel ball inside it.
　　Insert ball bearings instead of the usual easy to use features of deep groove ball bearings are mainly for loading and unloading easy, spherical, insert ball bearing standard tolerances is: Sunnegga outside reduction, bore plus tolerances thus ensuring works with axis of the light;
Each set of insert ball bearings are not independently to use, he must have the housing within the overall machine patrons spherical bearing block with various shape overall coordination in place suitable for a variety of structures used.