| As the most widely used in the production sector,the cutting machine has been paid much attention to the researchers for many years,and the traditional design method can not meet the development speed of modern society.In this thesis,with a 20 mm bar Q235 A as an example,using CAD / CAE technology,combined with virtual prototyping technology,using radial clamping method a level-type precision shearing device had been designed and the virtual model of the device h ad been established.Several key parts are optimized through the numerical analysis.The main results of this thesis are as follows:1)Summed up the work of the existing shear characteristics,analysis of their respective strengths and weaknesses.This thesis discusses the background of virtual prototyping technology,the present situation of development,and the development trend of virtual prototyping technology in the future of large data.2)The geometrical relations of bar shear are discussed,and the principle of several kinds of precise cutting modes of bar is compared.It is concluded that the cross section quality of radial clamping shear is better.The stress process and stress state of bar shear are analyzed.Several main factors affecting the quality of section are studied.3)A kind of lever type precision shearing device is designed by using the principle of radial clamping and lever technology.The principle of radial clamping is discussed in detail,and the general assembly drawing of the lever type precision shearing device is given and completed.The key components of the design,including the lever structure,cutting edge structure,the return device,clearance adjustment device,positioning and discharge devices.And the work flow of lever-type shearing device is briefly introduced.4)According to the key components designed,UG NX software is used to complete the geometric modeling of the parts,and then the virtual assembly is carried out.The explosion diagram of the device is given and the mechanism is checked.5)The motion characteristics of the moving parts are analyzed,and the displacement,velocity and acceleration of the moving parameters of the moving parts are analyzed.The shear efficiency of the mechanism is estimated and the rationality of the shearing mechanism is verified.6)The dynamic characteristics of the mechanism are analyzed,the modal of the mechanism,the stiffness and strength of the key parts during the cutting process and the fatigue life are analyzed,and the strength and stiffness of the mechanism are checked.The results show that the designed lever bar shearing device can achieve the intended working target,and the strength and rigidity of the main parts meet the working requirements.Compared with the existing devices,the device has the characteristics of good working stability and high working efficiency.At the same time seeing in the product design process,the contribution of virtual prototyping technology,from design to simulation,to facilitate the design staff found errors,correct the error,the actual production of the product to provide data reference. |
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