Research On Vibration Characteristics And Design Of Special Miller For Deep Via-Hole Key Groove

In view of the fact that there is little research on the key groove processing technology of deep via-hole for slender cylindrical parts and the traditional processing methods are difficult to realize,a special deep via-hole key groove milling machine was designed,which can mill the longest slender cylindrical parts.It can reach 2000mm,the inner diameter is not less than 60 mm,and the aspect ratio of deep holes is not more than 25.This article mainly carried out the structural design and vibration characteristics analysis of the special milling machine for deep via-hole key groove,including the overall plan design,the static and dynamic characteristics analysis and design of the key parts of the machine tool,the design of the machine tool transmission system,the vibration characteristics of the machine tool spindle and the influencing factors of the processing process parameters.Research etc.The research content and conclusions of this paper are as follows:(1)In view of the processing requirements of the keyway in the slender cylindrical parts with no more than 2000 mm,inner diameter no less than 60 mm,and deep hole length-to-diameter ratio no more than 25,the deep via-hole key groove was designed considering the processing environment in the narrow hole of the workpiece to be processed The overall plan of the special milling machine;Carried out the plan design of the milling machine shaft system,transmission system and auxiliary parts base guide rail and clamping and positioning device,designed the machine tool processing motion plan,and then carried out the design of the main technical parameters,including the machine tool processing capacity parameters,spindle speed,feed speed And the calculation and selection of the motor power,the technical parameter table of the deep via-hole key groove milling machine is obtained.(2)According to the overall plan design of the deep via-hole key groove milling machine,the structure design and check calculation of the key parts of the machine tool are carried out.The main transmission system of the milling machine adopts the motor-driven main shaft to transmit the power to the milling cutter through the bevel gear transmission,and the selection and calculation of the transmission bevel gear;The feed drive system uses a motor with a reducer to drive the ball screw nut pair to drive the work slide to slide linearly along the guide rail.The model and specification of the ball screw was calculated as GD4005-3 2400/2200.The structural parameter design of the hollow shafting main shaft,hollow tube and guide rod has been completed.The maximum deflection deformation of the three supporting structure of the main shaft is 0.0129 mm.It was calculated that the positioning error of the adjustable height V-shaped block in the radial direction of the workpiece is 0.0282 mm.(3)The static and dynamic characteristics of the key components of the deep via-hole key groove milling machine were analyzed.The static characteristics of the hollow tube are better.The modal analysis results show that as the order increases,the vibration displacement response of the hollow tube in the radial direction increases,reaching 9.735mm at the 5th order.Discuss the dynamics of different hollow tube wall thicknesses,the influence of characteristics is the smallest vibration displacement when the wall thickness is 6mm.The main shaft,hollow tube,milling head,and guide rod are combined into a hollow shaft system.The maximum static deformation variable of the main shaft in the hollow shaft system is 0.3855 mm.At the same time,the vibration response and the vibration displacement amplitude of the main shaft under the variable support of the hollow shaft system were explored.With the movement of the supporting point,there is a tendency to first become smaller and then larger.The maximum vibration displacement amplitude is 0.134 mm when the support point moves 0 mm,and the minimum vibration displacement amplitude of the spindle reaches 0.078 mm when the support point moves 800 mm.(4)In order to explore the vibration characteristics of the flexible spindle during the processing of the special milling machine for deep via-hole key groove,combined with the machine tool structure,the Euler-Bernoulli theory was used to derive the radial vibration displacement response function of the flexible spindle,and the spindle under the single factor change of process parameters The vibration displacement response curve.Inventor was used for modal analysis of the spindle milling system,and the vibration displacement response cloud diagram was obtained.According to the vibration model of the flexible spindle,a prototype vibration test of a deep via-hole key groove milling machine was carried out.The theoretical and experimental values of the spindle vibration displacement amplitude were compared under different processing parameters.The relative error was within 12%,indicating that the theory and the experiment are consistent.The performance is good,which verifies the correctness of the derivation of the spindle vibration theoretical model.