This kind of bearing is suitable for the parts in which the radial
size is specially limited. Since the bearing has not collar, the
surface of shaft journal and the surface of housing inner bore are
directly acted as rolling face. It is requested that the hardness,
surface roughness and size accuracy of shaft journal surface and
housing inner bore surface fitted with it be adaptable to the
collar of bearing. Another pivot cylinder is modified as flat
cylinder with M-type cage structure. Its speed performance is
greatly improved.
