Study On Transmission And Motion Characteristics Of Swing-linked Indexing Cam Mechanism

Nowadays,dividing devices are frequently used in industries where the degrees of automation are higher,such as textile,machine tools,food,electronics,packaging,etc.Thus higher productivity could be achieved.Cam indexing devices,also known as cam indexers,possess advantages of accurate positioning,smooth operation,and compact structure,which make them widely used.There are 3 kinds of commonly used cam indexing mechanisms.The structure of parallel indexing cam mechanism is simple and the cost of it is low.It is used when the input shaft and the output shaft are parallel.The cylindrical indexing cam mechanism and Globoid indexing cam mechanism are applied to the occasion where the input shaft and the output shaft are interlaced and vertical.The first one has strong bearing capacity,and the second one possess advantage of smooth operation and thus can be used in high-speed indexing application.Many studies about creative cam indexing mechanisms have been carried out and lots of new cam indexing mechanisms such as planetary indexing cam mechanism and coaxial cam-linkage mechanism have been proposed and might have great potentials for wide application.The study object of this paper is swing-linked indexing cam mechanism,which is a coaxial intermittent indexing mechanism.Multiple dwells could be reached within one revolution of the input shaft.It is characterized with simple and compact structure and has great potentials for wide application.Specifically,the research carried out in this paper mainly involves:(1)Research on the transmission principle of swing-linked indexing cam mechanism.The equation of the cam's real profile is derived and multiple significant parameters of the mechanism are defined.The position relationship between two enveloping dots from two different rollers at the same time are analyzed,and a necessary rule is proposed which could ensure the engagement between the rollers and cams.Based on the position relationship between two enveloping dots,another method that can determine equation for the cam real profile is proposed.By use of MATLAB,the kinematic conditions of the mechanism are preliminarily simulated.(2)The definition,characteristics and application of cam curves.The equations for pressure angle and curvature are furtherly derived,and constrains for pressure angle and curvature are illustrated.The relationship between two pressure angles,which are defined between two contact dots from two different cams,are analyzed.The effects caused by the variation of mechanism parameters,such as degrees of division and motion patterns,to the pressure angle and curvature,are analyzed under the condition of a set of given parameters.(3)The 3-dimentional modeling methods of the cam are discussed.Specifically,two different modeling methods,including traditional cam modeling method which takes advantage of numeric calculation software,and enveloping method based on CATIA's secondary development technique,are involved and hence comparison of the two methods are carried out.Finally,the 3-dimentional models of the whole mechanism are assembled and by use of ADAMS,kinematical simulation could be completed.(4)The calculation of cam's contact stress.Based on MATLAB,the parametric analyzing interface of swing-linked indexing cam mechanism is designed,which could be of great help for the design of this kind of cam indexing mechanisms by providing references for analysis and choices of parameters and thus laying the foundations for its wider application.