Hypostatic Modeling And NC Machining Of The Roller Sprockets 3D Parametric

Chain Drives has been applied in some fields,such as framing,mining,lifting, transportation,metallurgy,architecture,petroleum,chemical industry and other mechanical fields.Roller chain is the widest application in the chain drives.It consists of the chain,the drive sprocket and the driven sprocket.Roller sprockets have some special dentiform teeth.Depending upon the meshing which lies in between chain teeth and chain nodes,it can transfer the desired movement.The teeth of roller sprockets have the national standards.According to the standard of GB/T 1243—1997,the form of "three arcs and one line" is used in the teeth of roller sprockets.In fact,roller sprockets have some types,so it's design must have many steps,such as checking table,calculating,drawing,etc.It has many shortcomings,for example the great repetitive work,the low efficiency,the long calculation period and many errors.The alveolar shape of roller sprockets can be machined by the according normal cutters.For only one or a few parts,machining of roller sprockets is more expensive. If it is machined by normal milling machine,it will have the high requirements for workers' technique and also produce the inaccurate teeth.In this circumstance,this thesis which makes use of the parametric function of 3D machine software—Autodesk Inventor and combines Excel,the database manage tool,and computer aided design software—Mastercam designs and NC machines the 3D parametric of roller sprockets.The main tasks are finished in this paper;(1) Make use of the parametric technique to the 3D parametric model of roller sprockets. After the system is updated,it will automatically draw the 3D model of roller sprockets when designers choose the different parameters.It can reduce the time that repetitively establish model and can increase the efficiency of design.(2)3D model which is produced by Autodesk Inventor is transferred to the Mastercam.Making use of CAD/CAM of Mastercam and setting reasonable parameters,the correct NC machining procedure is created,and then this procedure is transmitted into NC milling machine so that this can realize the NC machining of roller sprockets,thus it can shorten the productive period of roller sprockets and increase processing precision.