Analysis Of The Static And Dynamic Performances Of The High-speed Toolholder With Hydraulic Expansion Driven By Centrifugal Force

The toolholder, as the core of tool system, has the vital impact on guaranteeing the exact orientation of tool on the machine tool and ensuring the processing quality. With the fast development of the High Speed Machine technology, the HSK high-speed toolholder is used widely. However, there is the expansion clearance between HSK toolholder and spindle taper hole with the influence of centrifugal force under the higher speed, which leads to toolholder′s positioning and lamping losing efficacy and limits raising of the tool-system limiting speed more. To solve that problem, the high-speed toolholder with hydraulic expansion driven by centrifugal force was designed and its main performance parameters were analyzed, which provides foundation for toolholder′s practical application.Here were the static and dynamic performances of the new high-speed toolholder studied further combining theoretical calculation and numerical analysis. The research contents are listed in detail as follows:(1) The distribution rule of contact pressure on the new tool-system interface with the increasing of spindle speed was obtained by numerical analysis, and the limiting speed was ascertained. The stiffness model of the new tool system was established, the interface stiffness and the allowable flexural moment were got through theoretical calculation, which were used for mutual authentication with the result of numerical analysis.(2) The largest unbalance magnitude was figured out under the limiting speed and the dynamic balancing precision grade was ascertained aiming at the potential unbalance situation of the new high-speed toolholder. The vibration mechanical model of toolholder regarding the inertial centrifugal force caused by the unbalance magnitude as an exciting force was established; the dynamic deflection of the toolholder axis was obtained through solving the motion differential equations of system; the vibration rule of toolholder was analyzed and the measures of mitigating vibration were discussed.(3) The liquid-solid(hydraulic oil in the compensation system and the body of toolholder) coupling modal and the harmonic response of the new high-speed toolholder were studied. The six lowest modals and the amplitude-frequency response curves of piston-spring and loading point of toolholder′s body under the simple harmonic load were extracted, which were used to compare with modal and harmonic response of the toolholder without hydraulic oil and HSK-A63, and the influence of hydraulic oil on the dynamic performance of the new high-speed toolholder was analyzed.