| So all kinds of specific gear tooth profile including modification of standard involute tooth profile are being developed and used to satisfy different tasks.At present,most of the NC hobbing method is according to normal profile modification,and then modify the work-piece.But so far their generation of easy and low cost has not been solved completely.So study of their generation technology of specific gear tooth profile is imperative under the situation.Analyze and summarize all kinds of machining method that may have of tooth profile surface from relative kinematics at first.Study on the NC hobbing method of cosine gear based on space meshing theory,NC machining simulation is made in the corresponding software.We further investigate the generation mechanism of interference,we and offers the method of controlling the axis's translation which can avoid the interference.Four simultaneous-control methods of CNC for hobbing cosine gear are demonstrated.In this dissertation the coordinate calculation is done perfectly,which is included cutter-setting position about cylindrical spur cosine gear,small cone angle cosine gear on the base of the optimization of process flow.The results show thatⅰ) Coordinate relation between the hob and the gear is established using the general tool which is used to product a standard involute gear.The space conversion matrix of hobbing movement is deduced.The discrete numerical expression of cutting points with arbitrary tooth profile is obtained and the movement controlling model of CNC gear-hobbing machine of the gear with arbitrary tooth profile is built.The process of NC machining simulation verified that the reliability of the movement controlling model of CNC gear-hobbing machine of the cosine tooth profile,ⅱ) Radial and axial translation are realized which controls the axis's movement,so that active control a certain amount of the over cutting and undercut according to normal profile modificationΔnj,and the movement controlling equation is obtained under not interfering, the main parameter:the amount of radius direction modification is eni,the amount of axial direction modification is eti,the rotational motion of hob isθi,and the rotational motion of cosine gear isφi.ⅲ) A new method of the cutter-setting coordinate calculation of cosine gear is demonstrated on the base of the optimization of process flow.Firstly, hobbing the roughcast according to the arithmetic of hobbing cylindrical spur cosine gear. Secondly,the center of hob which is moved from o1 to o3 is the same as the cylindrical spur cosine gear.Third,the arithmetic of the center of the cutter-setting coordinate calculation of cosine gear is the same as the small cone angle cosine gear begin from o3, so that the line CD is tangent to ellipse consistently. |
