Design Of The High-speed Tool Holder With Hydrallic Expansion Drived By Centrifugal Force

As an essential part of tool and the machine, high-speed tool system includes theconnection between spindles and tools holders, and the connection between tools and toolholders. So the key is the tool holders. The general BT tool systems with7:24taper didn’tapply to the high-speed machining, because the positioning accuracy of tool holder taper islow. The common HSK high speed tool holders with1:10taper and hollow thin-walledstructures, they positioned by double sided method, so the connection stiffness and repeatpositioning accuracy higher. They overcome the defect of the general BT tool holderspartly, but there are also some shortages. The interference between tapered surface andtapered hole can not make up the expansion gap at higher speed, and then make theconnection stiffness reduce, so they can not be processed normally.Now design a kind of hydraulic expansion type high-speed tool holder, which drivedby the centrifugal force to solve the centrifugal expansion problem. This tool holder had ashort solid cone and double-sided positioning structure. The flange of the holder hascylinder drived by centrifugal force. That is say, the piston moved by its own high-speedcentrifugal force. The hydraulic oil to Thin-walled oil cavity of the elastic expansionsleeve though the oil path, then generated radial elastic deformation of the tapered surface,to make up the expansion gap.The main research contents include:(1) The design of the new high-speed tool holder’s structure. Propose solution for theproblems, arrange the location of the components, and design the tool holder’s structure.Such as design the cylinder’s structure, design expansion sleeve’s structure and size ofother related components, analyze the relationship between each structure size parametersof the expansion sleeve and the performance of tool holder by ANSYS Workbench finiteelement software, and choose the best structure size.(2) Analysis of spindle-tool holder. Establish model of spindle-expansion sleeve-toolholder body firstly, calculate the deformation and stress of the new tool holder, get theresults and compare with each respective indicators of the standard same sized HSK tool holders.(3) Determine the limit speed of tool holder. Using the FEM to determine the limitspeed of the new tool holder, and analysis the relationship between speed and the contactpressure of the tapered surface and the interference sealing surface, which the clamp forceand interference is determined.(4) The connection performance analysis of spindle-tool holder. Analysis therelationship between speed, bending moment loads and connection performance of thespindle-tool holder detaily, and compare with the same specifications HSK high speed toolholders.The results show that, the limit speed of new kind high speed tool holder improvesignificantly compared with the same specifications HSK high speed tool holders. Sinceconnection stiffness higher in the high speed and low load condition, thus the new typehigh speed tool holder is more suitable for high speed and light-load processing.