Dynamic and static characteristics of a wide speed range machine tool spindle

The static and dynamic stiffnesses of spindle-bearing systems are examined. It is shown that for most general purpose spindle designs spring or hydraulically preloaded bearing arrangements can produce more rigid spindles than comentational bearing arrangements. It is also argued that adjustable preload enables bearing damping to be matched to the spindle-bearing system to give maximum dynamic stiffness. The RHP Variload bearing arrangement is introduced.