Double Circular-arc Gear Hob CAD System Research And Development

Double circular-arc gear hob is a direct production tool in machining process, whose performance directly affects the machining efficiency,and then affects surface quality and accuracy of double circular-arc gear.Thereby,the precise design of double circular-arc gear hob is of particularly importance.Through analyzing the design principle and manufacturing technology of double circular-arc gear hob,a breakthrough is made in design method.In traditional design process,baseline profile is used as the normal tooth profile of double circular-arc gear hob's basic worm,and axial tooth profile of double circular-arc gear hob uses helicoid formed by the movement in accordance with helical parameters of basic worm as helicoid of double circular-arc gear hob.With the close combination of the application of CAD technology and design theory,as well as the comprehensive utilization of parameterized feature modeling technology and object-oriented modular technology,the CAD system design of double circular-arc gear hob is achieved by secondary development of SolidWorks.Firstly,the calculation process of double circular-arc gear hob's tooth profile is introduced according to gear meshing theory,the GB/T12759-1991 double circular-arc gear hob as example.Start with tooth surface equation of double circular-arc gear's basic worm,rake face of double circular-arc gear hob at any front angle is obtained.And then axial profile of relief grinding wheel is gained according to relative kinematic relation between grinding wheel and hob in relief grinding.Secondly,through discussing the theory of form errors of gear hob,the major factors that impact the accuracy of double circular-arc gear hob is summed up,and the design scheme of double circular-arc gear hob tooth profile is ensured.Through error calculation of tooth profile and optimization of modeling,the grinding wheel's optimal design parameters of double circular-arc gear hob are obtained.And the parametric modeling process of double circular-arc gear hob is expounded.Thirdly,on the base of analyzing grinding principle of double circular-arc gear hob,the wheel shape's design parameters are taken advantage of.And machining simulation of relief grinding process of double circular-arc gear hob is carried out in VERICUT.The actual tooth profile is compared to theoretical form in order to verify the feasibility of design scheme.Finally,the overall framework of CAD system is established.Function module design ideas are adopted in this system,and the whole system is divided into five modules,such as the design and calculate of double circular-arc gear hob,the graphics processing of hob's design,relief grinding machining simulation of hob,the element analysis of hob cutter tooth,tool's database management.