Study On Mechanism And Device Of Ultrasound Milling Of Spiral Bevel Gears

Spiral bevel gear is a kind of gear with high load capacity,high transmission efficiency,smooth transmission and small noise.It is widely used in automobile,aircraft,machine tool and all kinds of mechanical products.Friction wear will inevitably exist in the process of gear meshing,and with the increasing of gear wear,abnormal vibration and noise will occur,ultimately lead to gear damage and failure.In order to reduce the wear and prolong the service life of gears,ultrasonic machining is applied to the manufacturing of spiral bevel gears,which can form regular micro texture on the surface of gears.The micro-grain can increase the thickness of oil film,reduce the friction torque,surface temperature and wear rate of gears,and reduce the meshing noise of gear.In this paper,the theory of ultrasonic hobbing and the ultrasonic vibration system is taken as the research object,there are several aspects mainly researched in the following:1.Based on the principle of traditional hobbing processing of spiral bevel gears,the ultrasonic frequency f and amplitude A were introduced to study the principle of ultrasonic hobbing.The effects of ultrasonic frequency f and cutter speed N on the micro-morphology of tooth surface were obtained.The space movement track of the blade in ultrasonic hobbing was analyzed,and the simulation cutter head in ultrasonic hobbing was generated by the way of guide line.According to the relevant processing parameters,the simulation experiment of tooth surface morphology was carried out and compared with the traditional hobbing tooth surface.It was proved that ultrasonic hobbing can improve the micro-morphology of tooth surface.2.According to the one-dimensional longitudinal vibration theory and the nonresonant design theory,the design of the ultrasonic transducer and the amplitude transformer was carried out on the basis of reasonable simplification of the milling cutter.Based on the wave equation of one-dimensional longitudinal vibration of variable cross-section rod,the mathematical model of ultrasonic transducer and amplitude transformer was established.According to the boundary conditions and coupling conditions of force and displacement,the resonant frequency equations of the ultrasonic transducer and the amplitude transformer were deduced,and their shape parameters were solved by Matlab software to achieved resonance.3.According to the size of the ultrasonic transducer and the amplitude transformer obtained by theoretical calculation,their three-dimensional models were established.The dynamic analysis and optimization of the ultrasonic vibration system were carried out in ANSYS software,which verifies the theoretical calculation of the amplitude transformer.According to the optimized size parameters of the ultrasonic vibration system,the material object was made.Then the impedance analysis experiment was tested,and the result was that the resonant frequency of the system is 24724 Hz,which met the design requirements,though has some error comparing with the theoretical design and finite element analysis.